diff --git a/pip_api/_installed_distributions.py b/pip_api/_installed_distributions.py
index 92bd58a..f4dc5c2 100644
--- a/pip_api/_installed_distributions.py
+++ b/pip_api/_installed_distributions.py
@@ -7,7 +7,7 @@
 from pip_api._call import call
 from pip_api.exceptions import PipError
 
-from pip_api._vendor.packaging.version import parse  # type: ignore
+from pip_api._vendor.packaging_legacy.version import parse  # type: ignore
 
 
 class Distribution:
diff --git a/pip_api/_vendor/packaging/__about__.py b/pip_api/_vendor/packaging/__about__.py
deleted file mode 100644
index e70d692..0000000
--- a/pip_api/_vendor/packaging/__about__.py
+++ /dev/null
@@ -1,26 +0,0 @@
-# This file is dual licensed under the terms of the Apache License, Version
-# 2.0, and the BSD License. See the LICENSE file in the root of this repository
-# for complete details.
-
-__all__ = [
-    "__title__",
-    "__summary__",
-    "__uri__",
-    "__version__",
-    "__author__",
-    "__email__",
-    "__license__",
-    "__copyright__",
-]
-
-__title__ = "packaging"
-__summary__ = "Core utilities for Python packages"
-__uri__ = "https://github.com/pypa/packaging"
-
-__version__ = "21.0"
-
-__author__ = "Donald Stufft and individual contributors"
-__email__ = "donald@stufft.io"
-
-__license__ = "BSD-2-Clause or Apache-2.0"
-__copyright__ = "2014-2019 %s" % __author__
diff --git a/pip_api/_vendor/packaging/__init__.py b/pip_api/_vendor/packaging/__init__.py
index 3c50c5d..22809cf 100644
--- a/pip_api/_vendor/packaging/__init__.py
+++ b/pip_api/_vendor/packaging/__init__.py
@@ -2,24 +2,14 @@
 # 2.0, and the BSD License. See the LICENSE file in the root of this repository
 # for complete details.
 
-from .__about__ import (
-    __author__,
-    __copyright__,
-    __email__,
-    __license__,
-    __summary__,
-    __title__,
-    __uri__,
-    __version__,
-)
+__title__ = "packaging"
+__summary__ = "Core utilities for Python packages"
+__uri__ = "https://github.com/pypa/packaging"
 
-__all__ = [
-    "__title__",
-    "__summary__",
-    "__uri__",
-    "__version__",
-    "__author__",
-    "__email__",
-    "__license__",
-    "__copyright__",
-]
+__version__ = "23.2"
+
+__author__ = "Donald Stufft and individual contributors"
+__email__ = "donald@stufft.io"
+
+__license__ = "BSD-2-Clause or Apache-2.0"
+__copyright__ = "2014 %s" % __author__
diff --git a/pip_api/_vendor/packaging/_elffile.py b/pip_api/_vendor/packaging/_elffile.py
new file mode 100644
index 0000000..6fb19b3
--- /dev/null
+++ b/pip_api/_vendor/packaging/_elffile.py
@@ -0,0 +1,108 @@
+"""
+ELF file parser.
+
+This provides a class ``ELFFile`` that parses an ELF executable in a similar
+interface to ``ZipFile``. Only the read interface is implemented.
+
+Based on: https://gist.github.com/lyssdod/f51579ae8d93c8657a5564aefc2ffbca
+ELF header: https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html
+"""
+
+import enum
+import os
+import struct
+from typing import IO, Optional, Tuple
+
+
+class ELFInvalid(ValueError):
+    pass
+
+
+class EIClass(enum.IntEnum):
+    C32 = 1
+    C64 = 2
+
+
+class EIData(enum.IntEnum):
+    Lsb = 1
+    Msb = 2
+
+
+class EMachine(enum.IntEnum):
+    I386 = 3
+    S390 = 22
+    Arm = 40
+    X8664 = 62
+    AArc64 = 183
+
+
+class ELFFile:
+    """
+    Representation of an ELF executable.
+    """
+
+    def __init__(self, f: IO[bytes]) -> None:
+        self._f = f
+
+        try:
+            ident = self._read("16B")
+        except struct.error:
+            raise ELFInvalid("unable to parse identification")
+        magic = bytes(ident[:4])
+        if magic != b"\x7fELF":
+            raise ELFInvalid(f"invalid magic: {magic!r}")
+
+        self.capacity = ident[4]  # Format for program header (bitness).
+        self.encoding = ident[5]  # Data structure encoding (endianness).
+
+        try:
+            # e_fmt: Format for program header.
+            # p_fmt: Format for section header.
+            # p_idx: Indexes to find p_type, p_offset, and p_filesz.
+            e_fmt, self._p_fmt, self._p_idx = {
+                (1, 1): ("<HHIIIIIHHH", "<IIIIIIII", (0, 1, 4)),  # 32-bit LSB.
+                (1, 2): (">HHIIIIIHHH", ">IIIIIIII", (0, 1, 4)),  # 32-bit MSB.
+                (2, 1): ("<HHIQQQIHHH", "<IIQQQQQQ", (0, 2, 5)),  # 64-bit LSB.
+                (2, 2): (">HHIQQQIHHH", ">IIQQQQQQ", (0, 2, 5)),  # 64-bit MSB.
+            }[(self.capacity, self.encoding)]
+        except KeyError:
+            raise ELFInvalid(
+                f"unrecognized capacity ({self.capacity}) or "
+                f"encoding ({self.encoding})"
+            )
+
+        try:
+            (
+                _,
+                self.machine,  # Architecture type.
+                _,
+                _,
+                self._e_phoff,  # Offset of program header.
+                _,
+                self.flags,  # Processor-specific flags.
+                _,
+                self._e_phentsize,  # Size of section.
+                self._e_phnum,  # Number of sections.
+            ) = self._read(e_fmt)
+        except struct.error as e:
+            raise ELFInvalid("unable to parse machine and section information") from e
+
+    def _read(self, fmt: str) -> Tuple[int, ...]:
+        return struct.unpack(fmt, self._f.read(struct.calcsize(fmt)))
+
+    @property
+    def interpreter(self) -> Optional[str]:
+        """
+        The path recorded in the ``PT_INTERP`` section header.
+        """
+        for index in range(self._e_phnum):
+            self._f.seek(self._e_phoff + self._e_phentsize * index)
+            try:
+                data = self._read(self._p_fmt)
+            except struct.error:
+                continue
+            if data[self._p_idx[0]] != 3:  # Not PT_INTERP.
+                continue
+            self._f.seek(data[self._p_idx[1]])
+            return os.fsdecode(self._f.read(data[self._p_idx[2]])).strip("\0")
+        return None
diff --git a/pip_api/_vendor/packaging/_manylinux.py b/pip_api/_vendor/packaging/_manylinux.py
index b0ed657..3705d50 100644
--- a/pip_api/_vendor/packaging/_manylinux.py
+++ b/pip_api/_vendor/packaging/_manylinux.py
@@ -1,122 +1,62 @@
 import collections
+import contextlib
 import functools
 import os
 import re
-import struct
 import sys
 import warnings
-from typing import IO, Dict, Iterator, NamedTuple, Optional, Tuple
-
-
-# Python does not provide platform information at sufficient granularity to
-# identify the architecture of the running executable in some cases, so we
-# determine it dynamically by reading the information from the running
-# process. This only applies on Linux, which uses the ELF format.
-class _ELFFileHeader:
-    # https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header
-    class _InvalidELFFileHeader(ValueError):
-        """
-        An invalid ELF file header was found.
-        """
-
-    ELF_MAGIC_NUMBER = 0x7F454C46
-    ELFCLASS32 = 1
-    ELFCLASS64 = 2
-    ELFDATA2LSB = 1
-    ELFDATA2MSB = 2
-    EM_386 = 3
-    EM_S390 = 22
-    EM_ARM = 40
-    EM_X86_64 = 62
-    EF_ARM_ABIMASK = 0xFF000000
-    EF_ARM_ABI_VER5 = 0x05000000
-    EF_ARM_ABI_FLOAT_HARD = 0x00000400
-
-    def __init__(self, file: IO[bytes]) -> None:
-        def unpack(fmt: str) -> int:
-            try:
-                data = file.read(struct.calcsize(fmt))
-                result: Tuple[int, ...] = struct.unpack(fmt, data)
-            except struct.error:
-                raise _ELFFileHeader._InvalidELFFileHeader()
-            return result[0]
-
-        self.e_ident_magic = unpack(">I")
-        if self.e_ident_magic != self.ELF_MAGIC_NUMBER:
-            raise _ELFFileHeader._InvalidELFFileHeader()
-        self.e_ident_class = unpack("B")
-        if self.e_ident_class not in {self.ELFCLASS32, self.ELFCLASS64}:
-            raise _ELFFileHeader._InvalidELFFileHeader()
-        self.e_ident_data = unpack("B")
-        if self.e_ident_data not in {self.ELFDATA2LSB, self.ELFDATA2MSB}:
-            raise _ELFFileHeader._InvalidELFFileHeader()
-        self.e_ident_version = unpack("B")
-        self.e_ident_osabi = unpack("B")
-        self.e_ident_abiversion = unpack("B")
-        self.e_ident_pad = file.read(7)
-        format_h = "<H" if self.e_ident_data == self.ELFDATA2LSB else ">H"
-        format_i = "<I" if self.e_ident_data == self.ELFDATA2LSB else ">I"
-        format_q = "<Q" if self.e_ident_data == self.ELFDATA2LSB else ">Q"
-        format_p = format_i if self.e_ident_class == self.ELFCLASS32 else format_q
-        self.e_type = unpack(format_h)
-        self.e_machine = unpack(format_h)
-        self.e_version = unpack(format_i)
-        self.e_entry = unpack(format_p)
-        self.e_phoff = unpack(format_p)
-        self.e_shoff = unpack(format_p)
-        self.e_flags = unpack(format_i)
-        self.e_ehsize = unpack(format_h)
-        self.e_phentsize = unpack(format_h)
-        self.e_phnum = unpack(format_h)
-        self.e_shentsize = unpack(format_h)
-        self.e_shnum = unpack(format_h)
-        self.e_shstrndx = unpack(format_h)
-
-
-def _get_elf_header() -> Optional[_ELFFileHeader]:
+from typing import Dict, Generator, Iterator, NamedTuple, Optional, Sequence, Tuple
+
+from ._elffile import EIClass, EIData, ELFFile, EMachine
+
+EF_ARM_ABIMASK = 0xFF000000
+EF_ARM_ABI_VER5 = 0x05000000
+EF_ARM_ABI_FLOAT_HARD = 0x00000400
+
+
+# `os.PathLike` not a generic type until Python 3.9, so sticking with `str`
+# as the type for `path` until then.
+@contextlib.contextmanager
+def _parse_elf(path: str) -> Generator[Optional[ELFFile], None, None]:
     try:
-        with open(sys.executable, "rb") as f:
-            elf_header = _ELFFileHeader(f)
-    except (OSError, TypeError, _ELFFileHeader._InvalidELFFileHeader):
-        return None
-    return elf_header
+        with open(path, "rb") as f:
+            yield ELFFile(f)
+    except (OSError, TypeError, ValueError):
+        yield None
 
 
-def _is_linux_armhf() -> bool:
+def _is_linux_armhf(executable: str) -> bool:
     # hard-float ABI can be detected from the ELF header of the running
     # process
     # https://static.docs.arm.com/ihi0044/g/aaelf32.pdf
-    elf_header = _get_elf_header()
-    if elf_header is None:
-        return False
-    result = elf_header.e_ident_class == elf_header.ELFCLASS32
-    result &= elf_header.e_ident_data == elf_header.ELFDATA2LSB
-    result &= elf_header.e_machine == elf_header.EM_ARM
-    result &= (
-        elf_header.e_flags & elf_header.EF_ARM_ABIMASK
-    ) == elf_header.EF_ARM_ABI_VER5
-    result &= (
-        elf_header.e_flags & elf_header.EF_ARM_ABI_FLOAT_HARD
-    ) == elf_header.EF_ARM_ABI_FLOAT_HARD
-    return result
-
-
-def _is_linux_i686() -> bool:
-    elf_header = _get_elf_header()
-    if elf_header is None:
-        return False
-    result = elf_header.e_ident_class == elf_header.ELFCLASS32
-    result &= elf_header.e_ident_data == elf_header.ELFDATA2LSB
-    result &= elf_header.e_machine == elf_header.EM_386
-    return result
+    with _parse_elf(executable) as f:
+        return (
+            f is not None
+            and f.capacity == EIClass.C32
+            and f.encoding == EIData.Lsb
+            and f.machine == EMachine.Arm
+            and f.flags & EF_ARM_ABIMASK == EF_ARM_ABI_VER5
+            and f.flags & EF_ARM_ABI_FLOAT_HARD == EF_ARM_ABI_FLOAT_HARD
+        )
+
+
+def _is_linux_i686(executable: str) -> bool:
+    with _parse_elf(executable) as f:
+        return (
+            f is not None
+            and f.capacity == EIClass.C32
+            and f.encoding == EIData.Lsb
+            and f.machine == EMachine.I386
+        )
 
 
-def _have_compatible_abi(arch: str) -> bool:
-    if arch == "armv7l":
-        return _is_linux_armhf()
-    if arch == "i686":
-        return _is_linux_i686()
-    return arch in {"x86_64", "aarch64", "ppc64", "ppc64le", "s390x"}
+def _have_compatible_abi(executable: str, archs: Sequence[str]) -> bool:
+    if "armv7l" in archs:
+        return _is_linux_armhf(executable)
+    if "i686" in archs:
+        return _is_linux_i686(executable)
+    allowed_archs = {"x86_64", "aarch64", "ppc64", "ppc64le", "s390x", "loongarch64"}
+    return any(arch in allowed_archs for arch in archs)
 
 
 # If glibc ever changes its major version, we need to know what the last
@@ -141,10 +81,10 @@ def _glibc_version_string_confstr() -> Optional[str]:
     # platform module.
     # https://github.com/python/cpython/blob/fcf1d003bf4f0100c/Lib/platform.py#L175-L183
     try:
-        # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17".
-        version_string = os.confstr("CS_GNU_LIBC_VERSION")
+        # Should be a string like "glibc 2.17".
+        version_string: str = getattr(os, "confstr")("CS_GNU_LIBC_VERSION")
         assert version_string is not None
-        _, version = version_string.split()
+        _, version = version_string.rsplit()
     except (AssertionError, AttributeError, OSError, ValueError):
         # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
         return None
@@ -211,8 +151,8 @@ def _parse_glibc_version(version_str: str) -> Tuple[int, int]:
     m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)", version_str)
     if not m:
         warnings.warn(
-            "Expected glibc version with 2 components major.minor,"
-            " got: %s" % version_str,
+            f"Expected glibc version with 2 components major.minor,"
+            f" got: {version_str}",
             RuntimeWarning,
         )
         return -1, -1
@@ -228,13 +168,13 @@ def _get_glibc_version() -> Tuple[int, int]:
 
 
 # From PEP 513, PEP 600
-def _is_compatible(name: str, arch: str, version: _GLibCVersion) -> bool:
+def _is_compatible(arch: str, version: _GLibCVersion) -> bool:
     sys_glibc = _get_glibc_version()
     if sys_glibc < version:
         return False
     # Check for presence of _manylinux module.
     try:
-        import _manylinux  # type: ignore # noqa
+        import _manylinux  # noqa
     except ImportError:
         return True
     if hasattr(_manylinux, "manylinux_compatible"):
@@ -264,12 +204,22 @@ def _is_compatible(name: str, arch: str, version: _GLibCVersion) -> bool:
 }
 
 
-def platform_tags(linux: str, arch: str) -> Iterator[str]:
-    if not _have_compatible_abi(arch):
+def platform_tags(archs: Sequence[str]) -> Iterator[str]:
+    """Generate manylinux tags compatible to the current platform.
+
+    :param archs: Sequence of compatible architectures.
+        The first one shall be the closest to the actual architecture and be the part of
+        platform tag after the ``linux_`` prefix, e.g. ``x86_64``.
+        The ``linux_`` prefix is assumed as a prerequisite for the current platform to
+        be manylinux-compatible.
+
+    :returns: An iterator of compatible manylinux tags.
+    """
+    if not _have_compatible_abi(sys.executable, archs):
         return
     # Oldest glibc to be supported regardless of architecture is (2, 17).
     too_old_glibc2 = _GLibCVersion(2, 16)
-    if arch in {"x86_64", "i686"}:
+    if set(archs) & {"x86_64", "i686"}:
         # On x86/i686 also oldest glibc to be supported is (2, 5).
         too_old_glibc2 = _GLibCVersion(2, 4)
     current_glibc = _GLibCVersion(*_get_glibc_version())
@@ -283,19 +233,20 @@ def platform_tags(linux: str, arch: str) -> Iterator[str]:
     for glibc_major in range(current_glibc.major - 1, 1, -1):
         glibc_minor = _LAST_GLIBC_MINOR[glibc_major]
         glibc_max_list.append(_GLibCVersion(glibc_major, glibc_minor))
-    for glibc_max in glibc_max_list:
-        if glibc_max.major == too_old_glibc2.major:
-            min_minor = too_old_glibc2.minor
-        else:
-            # For other glibc major versions oldest supported is (x, 0).
-            min_minor = -1
-        for glibc_minor in range(glibc_max.minor, min_minor, -1):
-            glibc_version = _GLibCVersion(glibc_max.major, glibc_minor)
-            tag = "manylinux_{}_{}".format(*glibc_version)
-            if _is_compatible(tag, arch, glibc_version):
-                yield linux.replace("linux", tag)
-            # Handle the legacy manylinux1, manylinux2010, manylinux2014 tags.
-            if glibc_version in _LEGACY_MANYLINUX_MAP:
-                legacy_tag = _LEGACY_MANYLINUX_MAP[glibc_version]
-                if _is_compatible(legacy_tag, arch, glibc_version):
-                    yield linux.replace("linux", legacy_tag)
+    for arch in archs:
+        for glibc_max in glibc_max_list:
+            if glibc_max.major == too_old_glibc2.major:
+                min_minor = too_old_glibc2.minor
+            else:
+                # For other glibc major versions oldest supported is (x, 0).
+                min_minor = -1
+            for glibc_minor in range(glibc_max.minor, min_minor, -1):
+                glibc_version = _GLibCVersion(glibc_max.major, glibc_minor)
+                tag = "manylinux_{}_{}".format(*glibc_version)
+                if _is_compatible(arch, glibc_version):
+                    yield f"{tag}_{arch}"
+                # Handle the legacy manylinux1, manylinux2010, manylinux2014 tags.
+                if glibc_version in _LEGACY_MANYLINUX_MAP:
+                    legacy_tag = _LEGACY_MANYLINUX_MAP[glibc_version]
+                    if _is_compatible(arch, glibc_version):
+                        yield f"{legacy_tag}_{arch}"
diff --git a/pip_api/_vendor/packaging/_musllinux.py b/pip_api/_vendor/packaging/_musllinux.py
index 85450fa..86419df 100644
--- a/pip_api/_vendor/packaging/_musllinux.py
+++ b/pip_api/_vendor/packaging/_musllinux.py
@@ -4,68 +4,13 @@
 linked against musl, and what musl version is used.
 """
 
-import contextlib
 import functools
-import operator
-import os
 import re
-import struct
 import subprocess
 import sys
-from typing import IO, Iterator, NamedTuple, Optional, Tuple
+from typing import Iterator, NamedTuple, Optional, Sequence
 
-
-def _read_unpacked(f: IO[bytes], fmt: str) -> Tuple[int, ...]:
-    return struct.unpack(fmt, f.read(struct.calcsize(fmt)))
-
-
-def _parse_ld_musl_from_elf(f: IO[bytes]) -> Optional[str]:
-    """Detect musl libc location by parsing the Python executable.
-
-    Based on: https://gist.github.com/lyssdod/f51579ae8d93c8657a5564aefc2ffbca
-    ELF header: https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html
-    """
-    f.seek(0)
-    try:
-        ident = _read_unpacked(f, "16B")
-    except struct.error:
-        return None
-    if ident[:4] != tuple(b"\x7fELF"):  # Invalid magic, not ELF.
-        return None
-    f.seek(struct.calcsize("HHI"), 1)  # Skip file type, machine, and version.
-
-    try:
-        # e_fmt: Format for program header.
-        # p_fmt: Format for section header.
-        # p_idx: Indexes to find p_type, p_offset, and p_filesz.
-        e_fmt, p_fmt, p_idx = {
-            1: ("IIIIHHH", "IIIIIIII", (0, 1, 4)),  # 32-bit.
-            2: ("QQQIHHH", "IIQQQQQQ", (0, 2, 5)),  # 64-bit.
-        }[ident[4]]
-    except KeyError:
-        return None
-    else:
-        p_get = operator.itemgetter(*p_idx)
-
-    # Find the interpreter section and return its content.
-    try:
-        _, e_phoff, _, _, _, e_phentsize, e_phnum = _read_unpacked(f, e_fmt)
-    except struct.error:
-        return None
-    for i in range(e_phnum + 1):
-        f.seek(e_phoff + e_phentsize * i)
-        try:
-            p_type, p_offset, p_filesz = p_get(_read_unpacked(f, p_fmt))
-        except struct.error:
-            return None
-        if p_type != 3:  # Not PT_INTERP.
-            continue
-        f.seek(p_offset)
-        interpreter = os.fsdecode(f.read(p_filesz)).strip("\0")
-        if "musl" not in interpreter:
-            return None
-        return interpreter
-    return None
+from ._elffile import ELFFile
 
 
 class _MuslVersion(NamedTuple):
@@ -95,32 +40,34 @@ def _get_musl_version(executable: str) -> Optional[_MuslVersion]:
         Version 1.2.2
         Dynamic Program Loader
     """
-    with contextlib.ExitStack() as stack:
-        try:
-            f = stack.enter_context(open(executable, "rb"))
-        except IOError:
-            return None
-        ld = _parse_ld_musl_from_elf(f)
-    if not ld:
+    try:
+        with open(executable, "rb") as f:
+            ld = ELFFile(f).interpreter
+    except (OSError, TypeError, ValueError):
+        return None
+    if ld is None or "musl" not in ld:
         return None
-    proc = subprocess.run([ld], stderr=subprocess.PIPE, universal_newlines=True)
+    proc = subprocess.run([ld], stderr=subprocess.PIPE, text=True)
     return _parse_musl_version(proc.stderr)
 
 
-def platform_tags(arch: str) -> Iterator[str]:
+def platform_tags(archs: Sequence[str]) -> Iterator[str]:
     """Generate musllinux tags compatible to the current platform.
 
-    :param arch: Should be the part of platform tag after the ``linux_``
-        prefix, e.g. ``x86_64``. The ``linux_`` prefix is assumed as a
-        prerequisite for the current platform to be musllinux-compatible.
+    :param archs: Sequence of compatible architectures.
+        The first one shall be the closest to the actual architecture and be the part of
+        platform tag after the ``linux_`` prefix, e.g. ``x86_64``.
+        The ``linux_`` prefix is assumed as a prerequisite for the current platform to
+        be musllinux-compatible.
 
     :returns: An iterator of compatible musllinux tags.
     """
     sys_musl = _get_musl_version(sys.executable)
     if sys_musl is None:  # Python not dynamically linked against musl.
         return
-    for minor in range(sys_musl.minor, -1, -1):
-        yield f"musllinux_{sys_musl.major}_{minor}_{arch}"
+    for arch in archs:
+        for minor in range(sys_musl.minor, -1, -1):
+            yield f"musllinux_{sys_musl.major}_{minor}_{arch}"
 
 
 if __name__ == "__main__":  # pragma: no cover
diff --git a/pip_api/_vendor/packaging/_parser.py b/pip_api/_vendor/packaging/_parser.py
new file mode 100644
index 0000000..4576981
--- /dev/null
+++ b/pip_api/_vendor/packaging/_parser.py
@@ -0,0 +1,359 @@
+"""Handwritten parser of dependency specifiers.
+
+The docstring for each __parse_* function contains ENBF-inspired grammar representing
+the implementation.
+"""
+
+import ast
+from typing import Any, List, NamedTuple, Optional, Tuple, Union
+
+from ._tokenizer import DEFAULT_RULES, Tokenizer
+
+
+class Node:
+    def __init__(self, value: str) -> None:
+        self.value = value
+
+    def __str__(self) -> str:
+        return self.value
+
+    def __repr__(self) -> str:
+        return f"<{self.__class__.__name__}('{self}')>"
+
+    def serialize(self) -> str:
+        raise NotImplementedError
+
+
+class Variable(Node):
+    def serialize(self) -> str:
+        return str(self)
+
+
+class Value(Node):
+    def serialize(self) -> str:
+        return f'"{self}"'
+
+
+class Op(Node):
+    def serialize(self) -> str:
+        return str(self)
+
+
+MarkerVar = Union[Variable, Value]
+MarkerItem = Tuple[MarkerVar, Op, MarkerVar]
+# MarkerAtom = Union[MarkerItem, List["MarkerAtom"]]
+# MarkerList = List[Union["MarkerList", MarkerAtom, str]]
+# mypy does not support recursive type definition
+# https://github.com/python/mypy/issues/731
+MarkerAtom = Any
+MarkerList = List[Any]
+
+
+class ParsedRequirement(NamedTuple):
+    name: str
+    url: str
+    extras: List[str]
+    specifier: str
+    marker: Optional[MarkerList]
+
+
+# --------------------------------------------------------------------------------------
+# Recursive descent parser for dependency specifier
+# --------------------------------------------------------------------------------------
+def parse_requirement(source: str) -> ParsedRequirement:
+    return _parse_requirement(Tokenizer(source, rules=DEFAULT_RULES))
+
+
+def _parse_requirement(tokenizer: Tokenizer) -> ParsedRequirement:
+    """
+    requirement = WS? IDENTIFIER WS? extras WS? requirement_details
+    """
+    tokenizer.consume("WS")
+
+    name_token = tokenizer.expect(
+        "IDENTIFIER", expected="package name at the start of dependency specifier"
+    )
+    name = name_token.text
+    tokenizer.consume("WS")
+
+    extras = _parse_extras(tokenizer)
+    tokenizer.consume("WS")
+
+    url, specifier, marker = _parse_requirement_details(tokenizer)
+    tokenizer.expect("END", expected="end of dependency specifier")
+
+    return ParsedRequirement(name, url, extras, specifier, marker)
+
+
+def _parse_requirement_details(
+    tokenizer: Tokenizer,
+) -> Tuple[str, str, Optional[MarkerList]]:
+    """
+    requirement_details = AT URL (WS requirement_marker?)?
+                        | specifier WS? (requirement_marker)?
+    """
+
+    specifier = ""
+    url = ""
+    marker = None
+
+    if tokenizer.check("AT"):
+        tokenizer.read()
+        tokenizer.consume("WS")
+
+        url_start = tokenizer.position
+        url = tokenizer.expect("URL", expected="URL after @").text
+        if tokenizer.check("END", peek=True):
+            return (url, specifier, marker)
+
+        tokenizer.expect("WS", expected="whitespace after URL")
+
+        # The input might end after whitespace.
+        if tokenizer.check("END", peek=True):
+            return (url, specifier, marker)
+
+        marker = _parse_requirement_marker(
+            tokenizer, span_start=url_start, after="URL and whitespace"
+        )
+    else:
+        specifier_start = tokenizer.position
+        specifier = _parse_specifier(tokenizer)
+        tokenizer.consume("WS")
+
+        if tokenizer.check("END", peek=True):
+            return (url, specifier, marker)
+
+        marker = _parse_requirement_marker(
+            tokenizer,
+            span_start=specifier_start,
+            after=(
+                "version specifier"
+                if specifier
+                else "name and no valid version specifier"
+            ),
+        )
+
+    return (url, specifier, marker)
+
+
+def _parse_requirement_marker(
+    tokenizer: Tokenizer, *, span_start: int, after: str
+) -> MarkerList:
+    """
+    requirement_marker = SEMICOLON marker WS?
+    """
+
+    if not tokenizer.check("SEMICOLON"):
+        tokenizer.raise_syntax_error(
+            f"Expected end or semicolon (after {after})",
+            span_start=span_start,
+        )
+    tokenizer.read()
+
+    marker = _parse_marker(tokenizer)
+    tokenizer.consume("WS")
+
+    return marker
+
+
+def _parse_extras(tokenizer: Tokenizer) -> List[str]:
+    """
+    extras = (LEFT_BRACKET wsp* extras_list? wsp* RIGHT_BRACKET)?
+    """
+    if not tokenizer.check("LEFT_BRACKET", peek=True):
+        return []
+
+    with tokenizer.enclosing_tokens(
+        "LEFT_BRACKET",
+        "RIGHT_BRACKET",
+        around="extras",
+    ):
+        tokenizer.consume("WS")
+        extras = _parse_extras_list(tokenizer)
+        tokenizer.consume("WS")
+
+    return extras
+
+
+def _parse_extras_list(tokenizer: Tokenizer) -> List[str]:
+    """
+    extras_list = identifier (wsp* ',' wsp* identifier)*
+    """
+    extras: List[str] = []
+
+    if not tokenizer.check("IDENTIFIER"):
+        return extras
+
+    extras.append(tokenizer.read().text)
+
+    while True:
+        tokenizer.consume("WS")
+        if tokenizer.check("IDENTIFIER", peek=True):
+            tokenizer.raise_syntax_error("Expected comma between extra names")
+        elif not tokenizer.check("COMMA"):
+            break
+
+        tokenizer.read()
+        tokenizer.consume("WS")
+
+        extra_token = tokenizer.expect("IDENTIFIER", expected="extra name after comma")
+        extras.append(extra_token.text)
+
+    return extras
+
+
+def _parse_specifier(tokenizer: Tokenizer) -> str:
+    """
+    specifier = LEFT_PARENTHESIS WS? version_many WS? RIGHT_PARENTHESIS
+              | WS? version_many WS?
+    """
+    with tokenizer.enclosing_tokens(
+        "LEFT_PARENTHESIS",
+        "RIGHT_PARENTHESIS",
+        around="version specifier",
+    ):
+        tokenizer.consume("WS")
+        parsed_specifiers = _parse_version_many(tokenizer)
+        tokenizer.consume("WS")
+
+    return parsed_specifiers
+
+
+def _parse_version_many(tokenizer: Tokenizer) -> str:
+    """
+    version_many = (SPECIFIER (WS? COMMA WS? SPECIFIER)*)?
+    """
+    parsed_specifiers = ""
+    while tokenizer.check("SPECIFIER"):
+        span_start = tokenizer.position
+        parsed_specifiers += tokenizer.read().text
+        if tokenizer.check("VERSION_PREFIX_TRAIL", peek=True):
+            tokenizer.raise_syntax_error(
+                ".* suffix can only be used with `==` or `!=` operators",
+                span_start=span_start,
+                span_end=tokenizer.position + 1,
+            )
+        if tokenizer.check("VERSION_LOCAL_LABEL_TRAIL", peek=True):
+            tokenizer.raise_syntax_error(
+                "Local version label can only be used with `==` or `!=` operators",
+                span_start=span_start,
+                span_end=tokenizer.position,
+            )
+        tokenizer.consume("WS")
+        if not tokenizer.check("COMMA"):
+            break
+        parsed_specifiers += tokenizer.read().text
+        tokenizer.consume("WS")
+
+    return parsed_specifiers
+
+
+# --------------------------------------------------------------------------------------
+# Recursive descent parser for marker expression
+# --------------------------------------------------------------------------------------
+def parse_marker(source: str) -> MarkerList:
+    return _parse_full_marker(Tokenizer(source, rules=DEFAULT_RULES))
+
+
+def _parse_full_marker(tokenizer: Tokenizer) -> MarkerList:
+    retval = _parse_marker(tokenizer)
+    tokenizer.expect("END", expected="end of marker expression")
+    return retval
+
+
+def _parse_marker(tokenizer: Tokenizer) -> MarkerList:
+    """
+    marker = marker_atom (BOOLOP marker_atom)+
+    """
+    expression = [_parse_marker_atom(tokenizer)]
+    while tokenizer.check("BOOLOP"):
+        token = tokenizer.read()
+        expr_right = _parse_marker_atom(tokenizer)
+        expression.extend((token.text, expr_right))
+    return expression
+
+
+def _parse_marker_atom(tokenizer: Tokenizer) -> MarkerAtom:
+    """
+    marker_atom = WS? LEFT_PARENTHESIS WS? marker WS? RIGHT_PARENTHESIS WS?
+                | WS? marker_item WS?
+    """
+
+    tokenizer.consume("WS")
+    if tokenizer.check("LEFT_PARENTHESIS", peek=True):
+        with tokenizer.enclosing_tokens(
+            "LEFT_PARENTHESIS",
+            "RIGHT_PARENTHESIS",
+            around="marker expression",
+        ):
+            tokenizer.consume("WS")
+            marker: MarkerAtom = _parse_marker(tokenizer)
+            tokenizer.consume("WS")
+    else:
+        marker = _parse_marker_item(tokenizer)
+    tokenizer.consume("WS")
+    return marker
+
+
+def _parse_marker_item(tokenizer: Tokenizer) -> MarkerItem:
+    """
+    marker_item = WS? marker_var WS? marker_op WS? marker_var WS?
+    """
+    tokenizer.consume("WS")
+    marker_var_left = _parse_marker_var(tokenizer)
+    tokenizer.consume("WS")
+    marker_op = _parse_marker_op(tokenizer)
+    tokenizer.consume("WS")
+    marker_var_right = _parse_marker_var(tokenizer)
+    tokenizer.consume("WS")
+    return (marker_var_left, marker_op, marker_var_right)
+
+
+def _parse_marker_var(tokenizer: Tokenizer) -> MarkerVar:
+    """
+    marker_var = VARIABLE | QUOTED_STRING
+    """
+    if tokenizer.check("VARIABLE"):
+        return process_env_var(tokenizer.read().text.replace(".", "_"))
+    elif tokenizer.check("QUOTED_STRING"):
+        return process_python_str(tokenizer.read().text)
+    else:
+        tokenizer.raise_syntax_error(
+            message="Expected a marker variable or quoted string"
+        )
+
+
+def process_env_var(env_var: str) -> Variable:
+    if (
+        env_var == "platform_python_implementation"
+        or env_var == "python_implementation"
+    ):
+        return Variable("platform_python_implementation")
+    else:
+        return Variable(env_var)
+
+
+def process_python_str(python_str: str) -> Value:
+    value = ast.literal_eval(python_str)
+    return Value(str(value))
+
+
+def _parse_marker_op(tokenizer: Tokenizer) -> Op:
+    """
+    marker_op = IN | NOT IN | OP
+    """
+    if tokenizer.check("IN"):
+        tokenizer.read()
+        return Op("in")
+    elif tokenizer.check("NOT"):
+        tokenizer.read()
+        tokenizer.expect("WS", expected="whitespace after 'not'")
+        tokenizer.expect("IN", expected="'in' after 'not'")
+        return Op("not in")
+    elif tokenizer.check("OP"):
+        return Op(tokenizer.read().text)
+    else:
+        return tokenizer.raise_syntax_error(
+            "Expected marker operator, one of "
+            "<=, <, !=, ==, >=, >, ~=, ===, in, not in"
+        )
diff --git a/pip_api/_vendor/packaging/_structures.py b/pip_api/_vendor/packaging/_structures.py
index 9515497..90a6465 100644
--- a/pip_api/_vendor/packaging/_structures.py
+++ b/pip_api/_vendor/packaging/_structures.py
@@ -19,9 +19,6 @@ def __le__(self, other: object) -> bool:
     def __eq__(self, other: object) -> bool:
         return isinstance(other, self.__class__)
 
-    def __ne__(self, other: object) -> bool:
-        return not isinstance(other, self.__class__)
-
     def __gt__(self, other: object) -> bool:
         return True
 
@@ -51,9 +48,6 @@ def __le__(self, other: object) -> bool:
     def __eq__(self, other: object) -> bool:
         return isinstance(other, self.__class__)
 
-    def __ne__(self, other: object) -> bool:
-        return not isinstance(other, self.__class__)
-
     def __gt__(self, other: object) -> bool:
         return False
 
diff --git a/pip_api/_vendor/packaging/_tokenizer.py b/pip_api/_vendor/packaging/_tokenizer.py
new file mode 100644
index 0000000..dd0d648
--- /dev/null
+++ b/pip_api/_vendor/packaging/_tokenizer.py
@@ -0,0 +1,192 @@
+import contextlib
+import re
+from dataclasses import dataclass
+from typing import Dict, Iterator, NoReturn, Optional, Tuple, Union
+
+from .specifiers import Specifier
+
+
+@dataclass
+class Token:
+    name: str
+    text: str
+    position: int
+
+
+class ParserSyntaxError(Exception):
+    """The provided source text could not be parsed correctly."""
+
+    def __init__(
+        self,
+        message: str,
+        *,
+        source: str,
+        span: Tuple[int, int],
+    ) -> None:
+        self.span = span
+        self.message = message
+        self.source = source
+
+        super().__init__()
+
+    def __str__(self) -> str:
+        marker = " " * self.span[0] + "~" * (self.span[1] - self.span[0]) + "^"
+        return "\n    ".join([self.message, self.source, marker])
+
+
+DEFAULT_RULES: "Dict[str, Union[str, re.Pattern[str]]]" = {
+    "LEFT_PARENTHESIS": r"\(",
+    "RIGHT_PARENTHESIS": r"\)",
+    "LEFT_BRACKET": r"\[",
+    "RIGHT_BRACKET": r"\]",
+    "SEMICOLON": r";",
+    "COMMA": r",",
+    "QUOTED_STRING": re.compile(
+        r"""
+            (
+                ('[^']*')
+                |
+                ("[^"]*")
+            )
+        """,
+        re.VERBOSE,
+    ),
+    "OP": r"(===|==|~=|!=|<=|>=|<|>)",
+    "BOOLOP": r"\b(or|and)\b",
+    "IN": r"\bin\b",
+    "NOT": r"\bnot\b",
+    "VARIABLE": re.compile(
+        r"""
+            \b(
+                python_version
+                |python_full_version
+                |os[._]name
+                |sys[._]platform
+                |platform_(release|system)
+                |platform[._](version|machine|python_implementation)
+                |python_implementation
+                |implementation_(name|version)
+                |extra
+            )\b
+        """,
+        re.VERBOSE,
+    ),
+    "SPECIFIER": re.compile(
+        Specifier._operator_regex_str + Specifier._version_regex_str,
+        re.VERBOSE | re.IGNORECASE,
+    ),
+    "AT": r"\@",
+    "URL": r"[^ \t]+",
+    "IDENTIFIER": r"\b[a-zA-Z0-9][a-zA-Z0-9._-]*\b",
+    "VERSION_PREFIX_TRAIL": r"\.\*",
+    "VERSION_LOCAL_LABEL_TRAIL": r"\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*",
+    "WS": r"[ \t]+",
+    "END": r"$",
+}
+
+
+class Tokenizer:
+    """Context-sensitive token parsing.
+
+    Provides methods to examine the input stream to check whether the next token
+    matches.
+    """
+
+    def __init__(
+        self,
+        source: str,
+        *,
+        rules: "Dict[str, Union[str, re.Pattern[str]]]",
+    ) -> None:
+        self.source = source
+        self.rules: Dict[str, re.Pattern[str]] = {
+            name: re.compile(pattern) for name, pattern in rules.items()
+        }
+        self.next_token: Optional[Token] = None
+        self.position = 0
+
+    def consume(self, name: str) -> None:
+        """Move beyond provided token name, if at current position."""
+        if self.check(name):
+            self.read()
+
+    def check(self, name: str, *, peek: bool = False) -> bool:
+        """Check whether the next token has the provided name.
+
+        By default, if the check succeeds, the token *must* be read before
+        another check. If `peek` is set to `True`, the token is not loaded and
+        would need to be checked again.
+        """
+        assert (
+            self.next_token is None
+        ), f"Cannot check for {name!r}, already have {self.next_token!r}"
+        assert name in self.rules, f"Unknown token name: {name!r}"
+
+        expression = self.rules[name]
+
+        match = expression.match(self.source, self.position)
+        if match is None:
+            return False
+        if not peek:
+            self.next_token = Token(name, match[0], self.position)
+        return True
+
+    def expect(self, name: str, *, expected: str) -> Token:
+        """Expect a certain token name next, failing with a syntax error otherwise.
+
+        The token is *not* read.
+        """
+        if not self.check(name):
+            raise self.raise_syntax_error(f"Expected {expected}")
+        return self.read()
+
+    def read(self) -> Token:
+        """Consume the next token and return it."""
+        token = self.next_token
+        assert token is not None
+
+        self.position += len(token.text)
+        self.next_token = None
+
+        return token
+
+    def raise_syntax_error(
+        self,
+        message: str,
+        *,
+        span_start: Optional[int] = None,
+        span_end: Optional[int] = None,
+    ) -> NoReturn:
+        """Raise ParserSyntaxError at the given position."""
+        span = (
+            self.position if span_start is None else span_start,
+            self.position if span_end is None else span_end,
+        )
+        raise ParserSyntaxError(
+            message,
+            source=self.source,
+            span=span,
+        )
+
+    @contextlib.contextmanager
+    def enclosing_tokens(
+        self, open_token: str, close_token: str, *, around: str
+    ) -> Iterator[None]:
+        if self.check(open_token):
+            open_position = self.position
+            self.read()
+        else:
+            open_position = None
+
+        yield
+
+        if open_position is None:
+            return
+
+        if not self.check(close_token):
+            self.raise_syntax_error(
+                f"Expected matching {close_token} for {open_token}, after {around}",
+                span_start=open_position,
+            )
+
+        self.read()
diff --git a/pip_api/_vendor/packaging/markers.py b/pip_api/_vendor/packaging/markers.py
index 87bbab7..8b98fca 100644
--- a/pip_api/_vendor/packaging/markers.py
+++ b/pip_api/_vendor/packaging/markers.py
@@ -8,19 +8,17 @@
 import sys
 from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
-from pip_api._vendor.pyparsing import (  # noqa: N817
-    Forward,
-    Group,
-    Literal as L,
-    ParseException,
-    ParseResults,
-    QuotedString,
-    ZeroOrMore,
-    stringEnd,
-    stringStart,
+from ._parser import (
+    MarkerAtom,
+    MarkerList,
+    Op,
+    Value,
+    Variable,
+    parse_marker as _parse_marker,
 )
-
+from ._tokenizer import ParserSyntaxError
 from .specifiers import InvalidSpecifier, Specifier
+from .utils import canonicalize_name
 
 __all__ = [
     "InvalidMarker",
@@ -52,101 +50,24 @@ class UndefinedEnvironmentName(ValueError):
     """
 
 
-class Node:
-    def __init__(self, value: Any) -> None:
-        self.value = value
-
-    def __str__(self) -> str:
-        return str(self.value)
-
-    def __repr__(self) -> str:
-        return f"<{self.__class__.__name__}('{self}')>"
-
-    def serialize(self) -> str:
-        raise NotImplementedError
-
-
-class Variable(Node):
-    def serialize(self) -> str:
-        return str(self)
-
-
-class Value(Node):
-    def serialize(self) -> str:
-        return f'"{self}"'
-
-
-class Op(Node):
-    def serialize(self) -> str:
-        return str(self)
-
-
-VARIABLE = (
-    L("implementation_version")
-    | L("platform_python_implementation")
-    | L("implementation_name")
-    | L("python_full_version")
-    | L("platform_release")
-    | L("platform_version")
-    | L("platform_machine")
-    | L("platform_system")
-    | L("python_version")
-    | L("sys_platform")
-    | L("os_name")
-    | L("os.name")  # PEP-345
-    | L("sys.platform")  # PEP-345
-    | L("platform.version")  # PEP-345
-    | L("platform.machine")  # PEP-345
-    | L("platform.python_implementation")  # PEP-345
-    | L("python_implementation")  # undocumented setuptools legacy
-    | L("extra")  # PEP-508
-)
-ALIASES = {
-    "os.name": "os_name",
-    "sys.platform": "sys_platform",
-    "platform.version": "platform_version",
-    "platform.machine": "platform_machine",
-    "platform.python_implementation": "platform_python_implementation",
-    "python_implementation": "platform_python_implementation",
-}
-VARIABLE.setParseAction(lambda s, l, t: Variable(ALIASES.get(t[0], t[0])))
-
-VERSION_CMP = (
-    L("===") | L("==") | L(">=") | L("<=") | L("!=") | L("~=") | L(">") | L("<")
-)
-
-MARKER_OP = VERSION_CMP | L("not in") | L("in")
-MARKER_OP.setParseAction(lambda s, l, t: Op(t[0]))
-
-MARKER_VALUE = QuotedString("'") | QuotedString('"')
-MARKER_VALUE.setParseAction(lambda s, l, t: Value(t[0]))
-
-BOOLOP = L("and") | L("or")
-
-MARKER_VAR = VARIABLE | MARKER_VALUE
-
-MARKER_ITEM = Group(MARKER_VAR + MARKER_OP + MARKER_VAR)
-MARKER_ITEM.setParseAction(lambda s, l, t: tuple(t[0]))
-
-LPAREN = L("(").suppress()
-RPAREN = L(")").suppress()
-
-MARKER_EXPR = Forward()
-MARKER_ATOM = MARKER_ITEM | Group(LPAREN + MARKER_EXPR + RPAREN)
-MARKER_EXPR << MARKER_ATOM + ZeroOrMore(BOOLOP + MARKER_EXPR)
-
-MARKER = stringStart + MARKER_EXPR + stringEnd
-
-
-def _coerce_parse_result(results: Union[ParseResults, List[Any]]) -> List[Any]:
-    if isinstance(results, ParseResults):
-        return [_coerce_parse_result(i) for i in results]
-    else:
-        return results
+def _normalize_extra_values(results: Any) -> Any:
+    """
+    Normalize extra values.
+    """
+    if isinstance(results[0], tuple):
+        lhs, op, rhs = results[0]
+        if isinstance(lhs, Variable) and lhs.value == "extra":
+            normalized_extra = canonicalize_name(rhs.value)
+            rhs = Value(normalized_extra)
+        elif isinstance(rhs, Variable) and rhs.value == "extra":
+            normalized_extra = canonicalize_name(lhs.value)
+            lhs = Value(normalized_extra)
+        results[0] = lhs, op, rhs
+    return results
 
 
 def _format_marker(
-    marker: Union[List[str], Tuple[Node, ...], str], first: Optional[bool] = True
+    marker: Union[List[str], MarkerAtom, str], first: Optional[bool] = True
 ) -> str:
 
     assert isinstance(marker, (list, tuple, str))
@@ -192,7 +113,7 @@ def _eval_op(lhs: str, op: Op, rhs: str) -> bool:
     except InvalidSpecifier:
         pass
     else:
-        return spec.contains(lhs)
+        return spec.contains(lhs, prereleases=True)
 
     oper: Optional[Operator] = _operators.get(op.serialize())
     if oper is None:
@@ -201,25 +122,19 @@ def _eval_op(lhs: str, op: Op, rhs: str) -> bool:
     return oper(lhs, rhs)
 
 
-class Undefined:
-    pass
-
+def _normalize(*values: str, key: str) -> Tuple[str, ...]:
+    # PEP 685 – Comparison of extra names for optional distribution dependencies
+    # https://peps.python.org/pep-0685/
+    # > When comparing extra names, tools MUST normalize the names being
+    # > compared using the semantics outlined in PEP 503 for names
+    if key == "extra":
+        return tuple(canonicalize_name(v) for v in values)
 
-_undefined = Undefined()
+    # other environment markers don't have such standards
+    return values
 
 
-def _get_env(environment: Dict[str, str], name: str) -> str:
-    value: Union[str, Undefined] = environment.get(name, _undefined)
-
-    if isinstance(value, Undefined):
-        raise UndefinedEnvironmentName(
-            f"{name!r} does not exist in evaluation environment."
-        )
-
-    return value
-
-
-def _evaluate_markers(markers: List[Any], environment: Dict[str, str]) -> bool:
+def _evaluate_markers(markers: MarkerList, environment: Dict[str, str]) -> bool:
     groups: List[List[bool]] = [[]]
 
     for marker in markers:
@@ -231,12 +146,15 @@ def _evaluate_markers(markers: List[Any], environment: Dict[str, str]) -> bool:
             lhs, op, rhs = marker
 
             if isinstance(lhs, Variable):
-                lhs_value = _get_env(environment, lhs.value)
+                environment_key = lhs.value
+                lhs_value = environment[environment_key]
                 rhs_value = rhs.value
             else:
                 lhs_value = lhs.value
-                rhs_value = _get_env(environment, rhs.value)
+                environment_key = rhs.value
+                rhs_value = environment[environment_key]
 
+            lhs_value, rhs_value = _normalize(lhs_value, rhs_value, key=environment_key)
             groups[-1].append(_eval_op(lhs_value, op, rhs_value))
         else:
             assert marker in ["and", "or"]
@@ -274,13 +192,29 @@ def default_environment() -> Dict[str, str]:
 
 class Marker:
     def __init__(self, marker: str) -> None:
+        # Note: We create a Marker object without calling this constructor in
+        #       packaging.requirements.Requirement. If any additional logic is
+        #       added here, make sure to mirror/adapt Requirement.
         try:
-            self._markers = _coerce_parse_result(MARKER.parseString(marker))
-        except ParseException as e:
-            raise InvalidMarker(
-                f"Invalid marker: {marker!r}, parse error at "
-                f"{marker[e.loc : e.loc + 8]!r}"
-            )
+            self._markers = _normalize_extra_values(_parse_marker(marker))
+            # The attribute `_markers` can be described in terms of a recursive type:
+            # MarkerList = List[Union[Tuple[Node, ...], str, MarkerList]]
+            #
+            # For example, the following expression:
+            # python_version > "3.6" or (python_version == "3.6" and os_name == "unix")
+            #
+            # is parsed into:
+            # [
+            #     (<Variable('python_version')>, <Op('>')>, <Value('3.6')>),
+            #     'and',
+            #     [
+            #         (<Variable('python_version')>, <Op('==')>, <Value('3.6')>),
+            #         'or',
+            #         (<Variable('os_name')>, <Op('==')>, <Value('unix')>)
+            #     ]
+            # ]
+        except ParserSyntaxError as e:
+            raise InvalidMarker(str(e)) from e
 
     def __str__(self) -> str:
         return _format_marker(self._markers)
@@ -288,6 +222,15 @@ def __str__(self) -> str:
     def __repr__(self) -> str:
         return f"<Marker('{self}')>"
 
+    def __hash__(self) -> int:
+        return hash((self.__class__.__name__, str(self)))
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, Marker):
+            return NotImplemented
+
+        return str(self) == str(other)
+
     def evaluate(self, environment: Optional[Dict[str, str]] = None) -> bool:
         """Evaluate a marker.
 
@@ -298,7 +241,12 @@ def evaluate(self, environment: Optional[Dict[str, str]] = None) -> bool:
         The environment is determined from the current Python process.
         """
         current_environment = default_environment()
+        current_environment["extra"] = ""
         if environment is not None:
             current_environment.update(environment)
+            # The API used to allow setting extra to None. We need to handle this
+            # case for backwards compatibility.
+            if current_environment["extra"] is None:
+                current_environment["extra"] = ""
 
         return _evaluate_markers(self._markers, current_environment)
diff --git a/pip_api/_vendor/packaging/metadata.py b/pip_api/_vendor/packaging/metadata.py
new file mode 100644
index 0000000..7b0e6a9
--- /dev/null
+++ b/pip_api/_vendor/packaging/metadata.py
@@ -0,0 +1,822 @@
+import email.feedparser
+import email.header
+import email.message
+import email.parser
+import email.policy
+import sys
+import typing
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Generic,
+    List,
+    Optional,
+    Tuple,
+    Type,
+    Union,
+    cast,
+)
+
+from . import requirements, specifiers, utils, version as version_module
+
+T = typing.TypeVar("T")
+if sys.version_info[:2] >= (3, 8):  # pragma: no cover
+    from typing import Literal, TypedDict
+else:  # pragma: no cover
+    if typing.TYPE_CHECKING:
+        from typing_extensions import Literal, TypedDict
+    else:
+        try:
+            from typing_extensions import Literal, TypedDict
+        except ImportError:
+
+            class Literal:
+                def __init_subclass__(*_args, **_kwargs):
+                    pass
+
+            class TypedDict:
+                def __init_subclass__(*_args, **_kwargs):
+                    pass
+
+
+try:
+    ExceptionGroup = __builtins__.ExceptionGroup  # type: ignore[attr-defined]
+except AttributeError:
+
+    class ExceptionGroup(Exception):  # type: ignore[no-redef]  # noqa: N818
+        """A minimal implementation of :external:exc:`ExceptionGroup` from Python 3.11.
+
+        If :external:exc:`ExceptionGroup` is already defined by Python itself,
+        that version is used instead.
+        """
+
+        message: str
+        exceptions: List[Exception]
+
+        def __init__(self, message: str, exceptions: List[Exception]) -> None:
+            self.message = message
+            self.exceptions = exceptions
+
+        def __repr__(self) -> str:
+            return f"{self.__class__.__name__}({self.message!r}, {self.exceptions!r})"
+
+
+class InvalidMetadata(ValueError):
+    """A metadata field contains invalid data."""
+
+    field: str
+    """The name of the field that contains invalid data."""
+
+    def __init__(self, field: str, message: str) -> None:
+        self.field = field
+        super().__init__(message)
+
+
+# The RawMetadata class attempts to make as few assumptions about the underlying
+# serialization formats as possible. The idea is that as long as a serialization
+# formats offer some very basic primitives in *some* way then we can support
+# serializing to and from that format.
+class RawMetadata(TypedDict, total=False):
+    """A dictionary of raw core metadata.
+
+    Each field in core metadata maps to a key of this dictionary (when data is
+    provided). The key is lower-case and underscores are used instead of dashes
+    compared to the equivalent core metadata field. Any core metadata field that
+    can be specified multiple times or can hold multiple values in a single
+    field have a key with a plural name. See :class:`Metadata` whose attributes
+    match the keys of this dictionary.
+
+    Core metadata fields that can be specified multiple times are stored as a
+    list or dict depending on which is appropriate for the field. Any fields
+    which hold multiple values in a single field are stored as a list.
+
+    """
+
+    # Metadata 1.0 - PEP 241
+    metadata_version: str
+    name: str
+    version: str
+    platforms: List[str]
+    summary: str
+    description: str
+    keywords: List[str]
+    home_page: str
+    author: str
+    author_email: str
+    license: str
+
+    # Metadata 1.1 - PEP 314
+    supported_platforms: List[str]
+    download_url: str
+    classifiers: List[str]
+    requires: List[str]
+    provides: List[str]
+    obsoletes: List[str]
+
+    # Metadata 1.2 - PEP 345
+    maintainer: str
+    maintainer_email: str
+    requires_dist: List[str]
+    provides_dist: List[str]
+    obsoletes_dist: List[str]
+    requires_python: str
+    requires_external: List[str]
+    project_urls: Dict[str, str]
+
+    # Metadata 2.0
+    # PEP 426 attempted to completely revamp the metadata format
+    # but got stuck without ever being able to build consensus on
+    # it and ultimately ended up withdrawn.
+    #
+    # However, a number of tools had started emitting METADATA with
+    # `2.0` Metadata-Version, so for historical reasons, this version
+    # was skipped.
+
+    # Metadata 2.1 - PEP 566
+    description_content_type: str
+    provides_extra: List[str]
+
+    # Metadata 2.2 - PEP 643
+    dynamic: List[str]
+
+    # Metadata 2.3 - PEP 685
+    # No new fields were added in PEP 685, just some edge case were
+    # tightened up to provide better interoptability.
+
+
+_STRING_FIELDS = {
+    "author",
+    "author_email",
+    "description",
+    "description_content_type",
+    "download_url",
+    "home_page",
+    "license",
+    "maintainer",
+    "maintainer_email",
+    "metadata_version",
+    "name",
+    "requires_python",
+    "summary",
+    "version",
+}
+
+_LIST_FIELDS = {
+    "classifiers",
+    "dynamic",
+    "obsoletes",
+    "obsoletes_dist",
+    "platforms",
+    "provides",
+    "provides_dist",
+    "provides_extra",
+    "requires",
+    "requires_dist",
+    "requires_external",
+    "supported_platforms",
+}
+
+_DICT_FIELDS = {
+    "project_urls",
+}
+
+
+def _parse_keywords(data: str) -> List[str]:
+    """Split a string of comma-separate keyboards into a list of keywords."""
+    return [k.strip() for k in data.split(",")]
+
+
+def _parse_project_urls(data: List[str]) -> Dict[str, str]:
+    """Parse a list of label/URL string pairings separated by a comma."""
+    urls = {}
+    for pair in data:
+        # Our logic is slightly tricky here as we want to try and do
+        # *something* reasonable with malformed data.
+        #
+        # The main thing that we have to worry about, is data that does
+        # not have a ',' at all to split the label from the Value. There
+        # isn't a singular right answer here, and we will fail validation
+        # later on (if the caller is validating) so it doesn't *really*
+        # matter, but since the missing value has to be an empty str
+        # and our return value is dict[str, str], if we let the key
+        # be the missing value, then they'd have multiple '' values that
+        # overwrite each other in a accumulating dict.
+        #
+        # The other potentional issue is that it's possible to have the
+        # same label multiple times in the metadata, with no solid "right"
+        # answer with what to do in that case. As such, we'll do the only
+        # thing we can, which is treat the field as unparseable and add it
+        # to our list of unparsed fields.
+        parts = [p.strip() for p in pair.split(",", 1)]
+        parts.extend([""] * (max(0, 2 - len(parts))))  # Ensure 2 items
+
+        # TODO: The spec doesn't say anything about if the keys should be
+        #       considered case sensitive or not... logically they should
+        #       be case-preserving and case-insensitive, but doing that
+        #       would open up more cases where we might have duplicate
+        #       entries.
+        label, url = parts
+        if label in urls:
+            # The label already exists in our set of urls, so this field
+            # is unparseable, and we can just add the whole thing to our
+            # unparseable data and stop processing it.
+            raise KeyError("duplicate labels in project urls")
+        urls[label] = url
+
+    return urls
+
+
+def _get_payload(msg: email.message.Message, source: Union[bytes, str]) -> str:
+    """Get the body of the message."""
+    # If our source is a str, then our caller has managed encodings for us,
+    # and we don't need to deal with it.
+    if isinstance(source, str):
+        payload: str = msg.get_payload()
+        return payload
+    # If our source is a bytes, then we're managing the encoding and we need
+    # to deal with it.
+    else:
+        bpayload: bytes = msg.get_payload(decode=True)
+        try:
+            return bpayload.decode("utf8", "strict")
+        except UnicodeDecodeError:
+            raise ValueError("payload in an invalid encoding")
+
+
+# The various parse_FORMAT functions here are intended to be as lenient as
+# possible in their parsing, while still returning a correctly typed
+# RawMetadata.
+#
+# To aid in this, we also generally want to do as little touching of the
+# data as possible, except where there are possibly some historic holdovers
+# that make valid data awkward to work with.
+#
+# While this is a lower level, intermediate format than our ``Metadata``
+# class, some light touch ups can make a massive difference in usability.
+
+# Map METADATA fields to RawMetadata.
+_EMAIL_TO_RAW_MAPPING = {
+    "author": "author",
+    "author-email": "author_email",
+    "classifier": "classifiers",
+    "description": "description",
+    "description-content-type": "description_content_type",
+    "download-url": "download_url",
+    "dynamic": "dynamic",
+    "home-page": "home_page",
+    "keywords": "keywords",
+    "license": "license",
+    "maintainer": "maintainer",
+    "maintainer-email": "maintainer_email",
+    "metadata-version": "metadata_version",
+    "name": "name",
+    "obsoletes": "obsoletes",
+    "obsoletes-dist": "obsoletes_dist",
+    "platform": "platforms",
+    "project-url": "project_urls",
+    "provides": "provides",
+    "provides-dist": "provides_dist",
+    "provides-extra": "provides_extra",
+    "requires": "requires",
+    "requires-dist": "requires_dist",
+    "requires-external": "requires_external",
+    "requires-python": "requires_python",
+    "summary": "summary",
+    "supported-platform": "supported_platforms",
+    "version": "version",
+}
+_RAW_TO_EMAIL_MAPPING = {raw: email for email, raw in _EMAIL_TO_RAW_MAPPING.items()}
+
+
+def parse_email(data: Union[bytes, str]) -> Tuple[RawMetadata, Dict[str, List[str]]]:
+    """Parse a distribution's metadata stored as email headers (e.g. from ``METADATA``).
+
+    This function returns a two-item tuple of dicts. The first dict is of
+    recognized fields from the core metadata specification. Fields that can be
+    parsed and translated into Python's built-in types are converted
+    appropriately. All other fields are left as-is. Fields that are allowed to
+    appear multiple times are stored as lists.
+
+    The second dict contains all other fields from the metadata. This includes
+    any unrecognized fields. It also includes any fields which are expected to
+    be parsed into a built-in type but were not formatted appropriately. Finally,
+    any fields that are expected to appear only once but are repeated are
+    included in this dict.
+
+    """
+    raw: Dict[str, Union[str, List[str], Dict[str, str]]] = {}
+    unparsed: Dict[str, List[str]] = {}
+
+    if isinstance(data, str):
+        parsed = email.parser.Parser(policy=email.policy.compat32).parsestr(data)
+    else:
+        parsed = email.parser.BytesParser(policy=email.policy.compat32).parsebytes(data)
+
+    # We have to wrap parsed.keys() in a set, because in the case of multiple
+    # values for a key (a list), the key will appear multiple times in the
+    # list of keys, but we're avoiding that by using get_all().
+    for name in frozenset(parsed.keys()):
+        # Header names in RFC are case insensitive, so we'll normalize to all
+        # lower case to make comparisons easier.
+        name = name.lower()
+
+        # We use get_all() here, even for fields that aren't multiple use,
+        # because otherwise someone could have e.g. two Name fields, and we
+        # would just silently ignore it rather than doing something about it.
+        headers = parsed.get_all(name) or []
+
+        # The way the email module works when parsing bytes is that it
+        # unconditionally decodes the bytes as ascii using the surrogateescape
+        # handler. When you pull that data back out (such as with get_all() ),
+        # it looks to see if the str has any surrogate escapes, and if it does
+        # it wraps it in a Header object instead of returning the string.
+        #
+        # As such, we'll look for those Header objects, and fix up the encoding.
+        value = []
+        # Flag if we have run into any issues processing the headers, thus
+        # signalling that the data belongs in 'unparsed'.
+        valid_encoding = True
+        for h in headers:
+            # It's unclear if this can return more types than just a Header or
+            # a str, so we'll just assert here to make sure.
+            assert isinstance(h, (email.header.Header, str))
+
+            # If it's a header object, we need to do our little dance to get
+            # the real data out of it. In cases where there is invalid data
+            # we're going to end up with mojibake, but there's no obvious, good
+            # way around that without reimplementing parts of the Header object
+            # ourselves.
+            #
+            # That should be fine since, if mojibacked happens, this key is
+            # going into the unparsed dict anyways.
+            if isinstance(h, email.header.Header):
+                # The Header object stores it's data as chunks, and each chunk
+                # can be independently encoded, so we'll need to check each
+                # of them.
+                chunks: List[Tuple[bytes, Optional[str]]] = []
+                for bin, encoding in email.header.decode_header(h):
+                    try:
+                        bin.decode("utf8", "strict")
+                    except UnicodeDecodeError:
+                        # Enable mojibake.
+                        encoding = "latin1"
+                        valid_encoding = False
+                    else:
+                        encoding = "utf8"
+                    chunks.append((bin, encoding))
+
+                # Turn our chunks back into a Header object, then let that
+                # Header object do the right thing to turn them into a
+                # string for us.
+                value.append(str(email.header.make_header(chunks)))
+            # This is already a string, so just add it.
+            else:
+                value.append(h)
+
+        # We've processed all of our values to get them into a list of str,
+        # but we may have mojibake data, in which case this is an unparsed
+        # field.
+        if not valid_encoding:
+            unparsed[name] = value
+            continue
+
+        raw_name = _EMAIL_TO_RAW_MAPPING.get(name)
+        if raw_name is None:
+            # This is a bit of a weird situation, we've encountered a key that
+            # we don't know what it means, so we don't know whether it's meant
+            # to be a list or not.
+            #
+            # Since we can't really tell one way or another, we'll just leave it
+            # as a list, even though it may be a single item list, because that's
+            # what makes the most sense for email headers.
+            unparsed[name] = value
+            continue
+
+        # If this is one of our string fields, then we'll check to see if our
+        # value is a list of a single item. If it is then we'll assume that
+        # it was emitted as a single string, and unwrap the str from inside
+        # the list.
+        #
+        # If it's any other kind of data, then we haven't the faintest clue
+        # what we should parse it as, and we have to just add it to our list
+        # of unparsed stuff.
+        if raw_name in _STRING_FIELDS and len(value) == 1:
+            raw[raw_name] = value[0]
+        # If this is one of our list of string fields, then we can just assign
+        # the value, since email *only* has strings, and our get_all() call
+        # above ensures that this is a list.
+        elif raw_name in _LIST_FIELDS:
+            raw[raw_name] = value
+        # Special Case: Keywords
+        # The keywords field is implemented in the metadata spec as a str,
+        # but it conceptually is a list of strings, and is serialized using
+        # ", ".join(keywords), so we'll do some light data massaging to turn
+        # this into what it logically is.
+        elif raw_name == "keywords" and len(value) == 1:
+            raw[raw_name] = _parse_keywords(value[0])
+        # Special Case: Project-URL
+        # The project urls is implemented in the metadata spec as a list of
+        # specially-formatted strings that represent a key and a value, which
+        # is fundamentally a mapping, however the email format doesn't support
+        # mappings in a sane way, so it was crammed into a list of strings
+        # instead.
+        #
+        # We will do a little light data massaging to turn this into a map as
+        # it logically should be.
+        elif raw_name == "project_urls":
+            try:
+                raw[raw_name] = _parse_project_urls(value)
+            except KeyError:
+                unparsed[name] = value
+        # Nothing that we've done has managed to parse this, so it'll just
+        # throw it in our unparseable data and move on.
+        else:
+            unparsed[name] = value
+
+    # We need to support getting the Description from the message payload in
+    # addition to getting it from the the headers. This does mean, though, there
+    # is the possibility of it being set both ways, in which case we put both
+    # in 'unparsed' since we don't know which is right.
+    try:
+        payload = _get_payload(parsed, data)
+    except ValueError:
+        unparsed.setdefault("description", []).append(
+            parsed.get_payload(decode=isinstance(data, bytes))
+        )
+    else:
+        if payload:
+            # Check to see if we've already got a description, if so then both
+            # it, and this body move to unparseable.
+            if "description" in raw:
+                description_header = cast(str, raw.pop("description"))
+                unparsed.setdefault("description", []).extend(
+                    [description_header, payload]
+                )
+            elif "description" in unparsed:
+                unparsed["description"].append(payload)
+            else:
+                raw["description"] = payload
+
+    # We need to cast our `raw` to a metadata, because a TypedDict only support
+    # literal key names, but we're computing our key names on purpose, but the
+    # way this function is implemented, our `TypedDict` can only have valid key
+    # names.
+    return cast(RawMetadata, raw), unparsed
+
+
+_NOT_FOUND = object()
+
+
+# Keep the two values in sync.
+_VALID_METADATA_VERSIONS = ["1.0", "1.1", "1.2", "2.1", "2.2", "2.3"]
+_MetadataVersion = Literal["1.0", "1.1", "1.2", "2.1", "2.2", "2.3"]
+
+_REQUIRED_ATTRS = frozenset(["metadata_version", "name", "version"])
+
+
+class _Validator(Generic[T]):
+    """Validate a metadata field.
+
+    All _process_*() methods correspond to a core metadata field. The method is
+    called with the field's raw value. If the raw value is valid it is returned
+    in its "enriched" form (e.g. ``version.Version`` for the ``Version`` field).
+    If the raw value is invalid, :exc:`InvalidMetadata` is raised (with a cause
+    as appropriate).
+    """
+
+    name: str
+    raw_name: str
+    added: _MetadataVersion
+
+    def __init__(
+        self,
+        *,
+        added: _MetadataVersion = "1.0",
+    ) -> None:
+        self.added = added
+
+    def __set_name__(self, _owner: "Metadata", name: str) -> None:
+        self.name = name
+        self.raw_name = _RAW_TO_EMAIL_MAPPING[name]
+
+    def __get__(self, instance: "Metadata", _owner: Type["Metadata"]) -> T:
+        # With Python 3.8, the caching can be replaced with functools.cached_property().
+        # No need to check the cache as attribute lookup will resolve into the
+        # instance's __dict__ before __get__ is called.
+        cache = instance.__dict__
+        try:
+            value = instance._raw[self.name]  # type: ignore[literal-required]
+        except KeyError:
+            if self.name in _STRING_FIELDS:
+                value = ""
+            elif self.name in _LIST_FIELDS:
+                value = []
+            elif self.name in _DICT_FIELDS:
+                value = {}
+            else:  # pragma: no cover
+                assert False
+
+        try:
+            converter: Callable[[Any], T] = getattr(self, f"_process_{self.name}")
+        except AttributeError:
+            pass
+        else:
+            value = converter(value)
+
+        cache[self.name] = value
+        try:
+            del instance._raw[self.name]  # type: ignore[misc]
+        except KeyError:
+            pass
+
+        return cast(T, value)
+
+    def _invalid_metadata(
+        self, msg: str, cause: Optional[Exception] = None
+    ) -> InvalidMetadata:
+        exc = InvalidMetadata(
+            self.raw_name, msg.format_map({"field": repr(self.raw_name)})
+        )
+        exc.__cause__ = cause
+        return exc
+
+    def _process_metadata_version(self, value: str) -> _MetadataVersion:
+        # Implicitly makes Metadata-Version required.
+        if value not in _VALID_METADATA_VERSIONS:
+            raise self._invalid_metadata(f"{value!r} is not a valid metadata version")
+        return cast(_MetadataVersion, value)
+
+    def _process_name(self, value: str) -> str:
+        if not value:
+            raise self._invalid_metadata("{field} is a required field")
+        # Validate the name as a side-effect.
+        try:
+            utils.canonicalize_name(value, validate=True)
+        except utils.InvalidName as exc:
+            raise self._invalid_metadata(
+                f"{value!r} is invalid for {{field}}", cause=exc
+            )
+        else:
+            return value
+
+    def _process_version(self, value: str) -> version_module.Version:
+        if not value:
+            raise self._invalid_metadata("{field} is a required field")
+        try:
+            return version_module.parse(value)
+        except version_module.InvalidVersion as exc:
+            raise self._invalid_metadata(
+                f"{value!r} is invalid for {{field}}", cause=exc
+            )
+
+    def _process_summary(self, value: str) -> str:
+        """Check the field contains no newlines."""
+        if "\n" in value:
+            raise self._invalid_metadata("{field} must be a single line")
+        return value
+
+    def _process_description_content_type(self, value: str) -> str:
+        content_types = {"text/plain", "text/x-rst", "text/markdown"}
+        message = email.message.EmailMessage()
+        message["content-type"] = value
+
+        content_type, parameters = (
+            # Defaults to `text/plain` if parsing failed.
+            message.get_content_type().lower(),
+            message["content-type"].params,
+        )
+        # Check if content-type is valid or defaulted to `text/plain` and thus was
+        # not parseable.
+        if content_type not in content_types or content_type not in value.lower():
+            raise self._invalid_metadata(
+                f"{{field}} must be one of {list(content_types)}, not {value!r}"
+            )
+
+        charset = parameters.get("charset", "UTF-8")
+        if charset != "UTF-8":
+            raise self._invalid_metadata(
+                f"{{field}} can only specify the UTF-8 charset, not {list(charset)}"
+            )
+
+        markdown_variants = {"GFM", "CommonMark"}
+        variant = parameters.get("variant", "GFM")  # Use an acceptable default.
+        if content_type == "text/markdown" and variant not in markdown_variants:
+            raise self._invalid_metadata(
+                f"valid Markdown variants for {{field}} are {list(markdown_variants)}, "
+                f"not {variant!r}",
+            )
+        return value
+
+    def _process_dynamic(self, value: List[str]) -> List[str]:
+        for dynamic_field in map(str.lower, value):
+            if dynamic_field in {"name", "version", "metadata-version"}:
+                raise self._invalid_metadata(
+                    f"{value!r} is not allowed as a dynamic field"
+                )
+            elif dynamic_field not in _EMAIL_TO_RAW_MAPPING:
+                raise self._invalid_metadata(f"{value!r} is not a valid dynamic field")
+        return list(map(str.lower, value))
+
+    def _process_provides_extra(
+        self,
+        value: List[str],
+    ) -> List[utils.NormalizedName]:
+        normalized_names = []
+        try:
+            for name in value:
+                normalized_names.append(utils.canonicalize_name(name, validate=True))
+        except utils.InvalidName as exc:
+            raise self._invalid_metadata(
+                f"{name!r} is invalid for {{field}}", cause=exc
+            )
+        else:
+            return normalized_names
+
+    def _process_requires_python(self, value: str) -> specifiers.SpecifierSet:
+        try:
+            return specifiers.SpecifierSet(value)
+        except specifiers.InvalidSpecifier as exc:
+            raise self._invalid_metadata(
+                f"{value!r} is invalid for {{field}}", cause=exc
+            )
+
+    def _process_requires_dist(
+        self,
+        value: List[str],
+    ) -> List[requirements.Requirement]:
+        reqs = []
+        try:
+            for req in value:
+                reqs.append(requirements.Requirement(req))
+        except requirements.InvalidRequirement as exc:
+            raise self._invalid_metadata(f"{req!r} is invalid for {{field}}", cause=exc)
+        else:
+            return reqs
+
+
+class Metadata:
+    """Representation of distribution metadata.
+
+    Compared to :class:`RawMetadata`, this class provides objects representing
+    metadata fields instead of only using built-in types. Any invalid metadata
+    will cause :exc:`InvalidMetadata` to be raised (with a
+    :py:attr:`~BaseException.__cause__` attribute as appropriate).
+    """
+
+    _raw: RawMetadata
+
+    @classmethod
+    def from_raw(cls, data: RawMetadata, *, validate: bool = True) -> "Metadata":
+        """Create an instance from :class:`RawMetadata`.
+
+        If *validate* is true, all metadata will be validated. All exceptions
+        related to validation will be gathered and raised as an :class:`ExceptionGroup`.
+        """
+        ins = cls()
+        ins._raw = data.copy()  # Mutations occur due to caching enriched values.
+
+        if validate:
+            exceptions: List[InvalidMetadata] = []
+            try:
+                metadata_version = ins.metadata_version
+                metadata_age = _VALID_METADATA_VERSIONS.index(metadata_version)
+            except InvalidMetadata as metadata_version_exc:
+                exceptions.append(metadata_version_exc)
+                metadata_version = None
+
+            # Make sure to check for the fields that are present, the required
+            # fields (so their absence can be reported).
+            fields_to_check = frozenset(ins._raw) | _REQUIRED_ATTRS
+            # Remove fields that have already been checked.
+            fields_to_check -= {"metadata_version"}
+
+            for key in fields_to_check:
+                try:
+                    if metadata_version:
+                        # Can't use getattr() as that triggers descriptor protocol which
+                        # will fail due to no value for the instance argument.
+                        try:
+                            field_metadata_version = cls.__dict__[key].added
+                        except KeyError:
+                            exc = InvalidMetadata(key, f"unrecognized field: {key!r}")
+                            exceptions.append(exc)
+                            continue
+                        field_age = _VALID_METADATA_VERSIONS.index(
+                            field_metadata_version
+                        )
+                        if field_age > metadata_age:
+                            field = _RAW_TO_EMAIL_MAPPING[key]
+                            exc = InvalidMetadata(
+                                field,
+                                "{field} introduced in metadata version "
+                                "{field_metadata_version}, not {metadata_version}",
+                            )
+                            exceptions.append(exc)
+                            continue
+                    getattr(ins, key)
+                except InvalidMetadata as exc:
+                    exceptions.append(exc)
+
+            if exceptions:
+                raise ExceptionGroup("invalid metadata", exceptions)
+
+        return ins
+
+    @classmethod
+    def from_email(
+        cls, data: Union[bytes, str], *, validate: bool = True
+    ) -> "Metadata":
+        """Parse metadata from email headers.
+
+        If *validate* is true, the metadata will be validated. All exceptions
+        related to validation will be gathered and raised as an :class:`ExceptionGroup`.
+        """
+        exceptions: list[InvalidMetadata] = []
+        raw, unparsed = parse_email(data)
+
+        if validate:
+            for unparsed_key in unparsed:
+                if unparsed_key in _EMAIL_TO_RAW_MAPPING:
+                    message = f"{unparsed_key!r} has invalid data"
+                else:
+                    message = f"unrecognized field: {unparsed_key!r}"
+                exceptions.append(InvalidMetadata(unparsed_key, message))
+
+            if exceptions:
+                raise ExceptionGroup("unparsed", exceptions)
+
+        try:
+            return cls.from_raw(raw, validate=validate)
+        except ExceptionGroup as exc_group:
+            exceptions.extend(exc_group.exceptions)
+            raise ExceptionGroup("invalid or unparsed metadata", exceptions) from None
+
+    metadata_version: _Validator[_MetadataVersion] = _Validator()
+    """:external:ref:`core-metadata-metadata-version`
+    (required; validated to be a valid metadata version)"""
+    name: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-name`
+    (required; validated using :func:`~packaging.utils.canonicalize_name` and its
+    *validate* parameter)"""
+    version: _Validator[version_module.Version] = _Validator()
+    """:external:ref:`core-metadata-version` (required)"""
+    dynamic: _Validator[List[str]] = _Validator(
+        added="2.2",
+    )
+    """:external:ref:`core-metadata-dynamic`
+    (validated against core metadata field names and lowercased)"""
+    platforms: _Validator[List[str]] = _Validator()
+    """:external:ref:`core-metadata-platform`"""
+    supported_platforms: _Validator[List[str]] = _Validator(added="1.1")
+    """:external:ref:`core-metadata-supported-platform`"""
+    summary: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-summary` (validated to contain no newlines)"""
+    description: _Validator[str] = _Validator()  # TODO 2.1: can be in body
+    """:external:ref:`core-metadata-description`"""
+    description_content_type: _Validator[str] = _Validator(added="2.1")
+    """:external:ref:`core-metadata-description-content-type` (validated)"""
+    keywords: _Validator[List[str]] = _Validator()
+    """:external:ref:`core-metadata-keywords`"""
+    home_page: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-home-page`"""
+    download_url: _Validator[str] = _Validator(added="1.1")
+    """:external:ref:`core-metadata-download-url`"""
+    author: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-author`"""
+    author_email: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-author-email`"""
+    maintainer: _Validator[str] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-maintainer`"""
+    maintainer_email: _Validator[str] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-maintainer-email`"""
+    license: _Validator[str] = _Validator()
+    """:external:ref:`core-metadata-license`"""
+    classifiers: _Validator[List[str]] = _Validator(added="1.1")
+    """:external:ref:`core-metadata-classifier`"""
+    requires_dist: _Validator[List[requirements.Requirement]] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-requires-dist`"""
+    requires_python: _Validator[specifiers.SpecifierSet] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-requires-python`"""
+    # Because `Requires-External` allows for non-PEP 440 version specifiers, we
+    # don't do any processing on the values.
+    requires_external: _Validator[List[str]] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-requires-external`"""
+    project_urls: _Validator[Dict[str, str]] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-project-url`"""
+    # PEP 685 lets us raise an error if an extra doesn't pass `Name` validation
+    # regardless of metadata version.
+    provides_extra: _Validator[List[utils.NormalizedName]] = _Validator(
+        added="2.1",
+    )
+    """:external:ref:`core-metadata-provides-extra`"""
+    provides_dist: _Validator[List[str]] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-provides-dist`"""
+    obsoletes_dist: _Validator[List[str]] = _Validator(added="1.2")
+    """:external:ref:`core-metadata-obsoletes-dist`"""
+    requires: _Validator[List[str]] = _Validator(added="1.1")
+    """``Requires`` (deprecated)"""
+    provides: _Validator[List[str]] = _Validator(added="1.1")
+    """``Provides`` (deprecated)"""
+    obsoletes: _Validator[List[str]] = _Validator(added="1.1")
+    """``Obsoletes`` (deprecated)"""
diff --git a/pip_api/_vendor/packaging/requirements.py b/pip_api/_vendor/packaging/requirements.py
index 303deef..0c00eba 100644
--- a/pip_api/_vendor/packaging/requirements.py
+++ b/pip_api/_vendor/packaging/requirements.py
@@ -2,26 +2,13 @@
 # 2.0, and the BSD License. See the LICENSE file in the root of this repository
 # for complete details.
 
-import re
-import string
-import urllib.parse
-from typing import List, Optional as TOptional, Set
-
-from pip_api._vendor.pyparsing import (  # noqa
-    Combine,
-    Literal as L,
-    Optional,
-    ParseException,
-    Regex,
-    Word,
-    ZeroOrMore,
-    originalTextFor,
-    stringEnd,
-    stringStart,
-)
-
-from .markers import MARKER_EXPR, Marker
-from .specifiers import LegacySpecifier, Specifier, SpecifierSet
+from typing import Any, Iterator, Optional, Set
+
+from ._parser import parse_requirement as _parse_requirement
+from ._tokenizer import ParserSyntaxError
+from .markers import Marker, _normalize_extra_values
+from .specifiers import SpecifierSet
+from .utils import canonicalize_name
 
 
 class InvalidRequirement(ValueError):
@@ -30,60 +17,6 @@ class InvalidRequirement(ValueError):
     """
 
 
-ALPHANUM = Word(string.ascii_letters + string.digits)
-
-LBRACKET = L("[").suppress()
-RBRACKET = L("]").suppress()
-LPAREN = L("(").suppress()
-RPAREN = L(")").suppress()
-COMMA = L(",").suppress()
-SEMICOLON = L(";").suppress()
-AT = L("@").suppress()
-
-PUNCTUATION = Word("-_.")
-IDENTIFIER_END = ALPHANUM | (ZeroOrMore(PUNCTUATION) + ALPHANUM)
-IDENTIFIER = Combine(ALPHANUM + ZeroOrMore(IDENTIFIER_END))
-
-NAME = IDENTIFIER("name")
-EXTRA = IDENTIFIER
-
-URI = Regex(r"[^ ]+")("url")
-URL = AT + URI
-
-EXTRAS_LIST = EXTRA + ZeroOrMore(COMMA + EXTRA)
-EXTRAS = (LBRACKET + Optional(EXTRAS_LIST) + RBRACKET)("extras")
-
-VERSION_PEP440 = Regex(Specifier._regex_str, re.VERBOSE | re.IGNORECASE)
-VERSION_LEGACY = Regex(LegacySpecifier._regex_str, re.VERBOSE | re.IGNORECASE)
-
-VERSION_ONE = VERSION_PEP440 ^ VERSION_LEGACY
-VERSION_MANY = Combine(
-    VERSION_ONE + ZeroOrMore(COMMA + VERSION_ONE), joinString=",", adjacent=False
-)("_raw_spec")
-_VERSION_SPEC = Optional((LPAREN + VERSION_MANY + RPAREN) | VERSION_MANY)
-_VERSION_SPEC.setParseAction(lambda s, l, t: t._raw_spec or "")
-
-VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")
-VERSION_SPEC.setParseAction(lambda s, l, t: t[1])
-
-MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")
-MARKER_EXPR.setParseAction(
-    lambda s, l, t: Marker(s[t._original_start : t._original_end])
-)
-MARKER_SEPARATOR = SEMICOLON
-MARKER = MARKER_SEPARATOR + MARKER_EXPR
-
-VERSION_AND_MARKER = VERSION_SPEC + Optional(MARKER)
-URL_AND_MARKER = URL + Optional(MARKER)
-
-NAMED_REQUIREMENT = NAME + Optional(EXTRAS) + (URL_AND_MARKER | VERSION_AND_MARKER)
-
-REQUIREMENT = stringStart + NAMED_REQUIREMENT + stringEnd
-# pyparsing isn't thread safe during initialization, so we do it eagerly, see
-# issue #104
-REQUIREMENT.parseString("x[]")
-
-
 class Requirement:
     """Parse a requirement.
 
@@ -99,48 +32,59 @@ class Requirement:
 
     def __init__(self, requirement_string: str) -> None:
         try:
-            req = REQUIREMENT.parseString(requirement_string)
-        except ParseException as e:
-            raise InvalidRequirement(
-                f'Parse error at "{ requirement_string[e.loc : e.loc + 8]!r}": {e.msg}'
-            )
-
-        self.name: str = req.name
-        if req.url:
-            parsed_url = urllib.parse.urlparse(req.url)
-            if parsed_url.scheme == "file":
-                if urllib.parse.urlunparse(parsed_url) != req.url:
-                    raise InvalidRequirement("Invalid URL given")
-            elif not (parsed_url.scheme and parsed_url.netloc) or (
-                not parsed_url.scheme and not parsed_url.netloc
-            ):
-                raise InvalidRequirement(f"Invalid URL: {req.url}")
-            self.url: TOptional[str] = req.url
-        else:
-            self.url = None
-        self.extras: Set[str] = set(req.extras.asList() if req.extras else [])
-        self.specifier: SpecifierSet = SpecifierSet(req.specifier)
-        self.marker: TOptional[Marker] = req.marker if req.marker else None
-
-    def __str__(self) -> str:
-        parts: List[str] = [self.name]
+            parsed = _parse_requirement(requirement_string)
+        except ParserSyntaxError as e:
+            raise InvalidRequirement(str(e)) from e
+
+        self.name: str = parsed.name
+        self.url: Optional[str] = parsed.url or None
+        self.extras: Set[str] = set(parsed.extras if parsed.extras else [])
+        self.specifier: SpecifierSet = SpecifierSet(parsed.specifier)
+        self.marker: Optional[Marker] = None
+        if parsed.marker is not None:
+            self.marker = Marker.__new__(Marker)
+            self.marker._markers = _normalize_extra_values(parsed.marker)
+
+    def _iter_parts(self, name: str) -> Iterator[str]:
+        yield name
 
         if self.extras:
             formatted_extras = ",".join(sorted(self.extras))
-            parts.append(f"[{formatted_extras}]")
+            yield f"[{formatted_extras}]"
 
         if self.specifier:
-            parts.append(str(self.specifier))
+            yield str(self.specifier)
 
         if self.url:
-            parts.append(f"@ {self.url}")
+            yield f"@ {self.url}"
             if self.marker:
-                parts.append(" ")
+                yield " "
 
         if self.marker:
-            parts.append(f"; {self.marker}")
+            yield f"; {self.marker}"
 
-        return "".join(parts)
+    def __str__(self) -> str:
+        return "".join(self._iter_parts(self.name))
 
     def __repr__(self) -> str:
         return f"<Requirement('{self}')>"
+
+    def __hash__(self) -> int:
+        return hash(
+            (
+                self.__class__.__name__,
+                *self._iter_parts(canonicalize_name(self.name)),
+            )
+        )
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, Requirement):
+            return NotImplemented
+
+        return (
+            canonicalize_name(self.name) == canonicalize_name(other.name)
+            and self.extras == other.extras
+            and self.specifier == other.specifier
+            and self.url == other.url
+            and self.marker == other.marker
+        )
diff --git a/pip_api/_vendor/packaging/specifiers.py b/pip_api/_vendor/packaging/specifiers.py
index ce66bd4..984986b 100644
--- a/pip_api/_vendor/packaging/specifiers.py
+++ b/pip_api/_vendor/packaging/specifiers.py
@@ -1,20 +1,22 @@
 # This file is dual licensed under the terms of the Apache License, Version
 # 2.0, and the BSD License. See the LICENSE file in the root of this repository
 # for complete details.
+"""
+.. testsetup::
+
+    from pip_api._vendor.packaging.specifiers import Specifier, SpecifierSet, InvalidSpecifier
+    from pip_api._vendor.packaging.version import Version
+"""
 
 import abc
-import functools
 import itertools
 import re
-import warnings
 from typing import (
     Callable,
-    Dict,
     Iterable,
     Iterator,
     List,
     Optional,
-    Pattern,
     Set,
     Tuple,
     TypeVar,
@@ -22,17 +24,28 @@
 )
 
 from .utils import canonicalize_version
-from .version import LegacyVersion, Version, parse
+from .version import Version
+
+UnparsedVersion = Union[Version, str]
+UnparsedVersionVar = TypeVar("UnparsedVersionVar", bound=UnparsedVersion)
+CallableOperator = Callable[[Version, str], bool]
 
-ParsedVersion = Union[Version, LegacyVersion]
-UnparsedVersion = Union[Version, LegacyVersion, str]
-VersionTypeVar = TypeVar("VersionTypeVar", bound=UnparsedVersion)
-CallableOperator = Callable[[ParsedVersion, str], bool]
+
+def _coerce_version(version: UnparsedVersion) -> Version:
+    if not isinstance(version, Version):
+        version = Version(version)
+    return version
 
 
 class InvalidSpecifier(ValueError):
     """
-    An invalid specifier was found, users should refer to PEP 440.
+    Raised when attempting to create a :class:`Specifier` with a specifier
+    string that is invalid.
+
+    >>> Specifier("lolwat")
+    Traceback (most recent call last):
+        ...
+    packaging.specifiers.InvalidSpecifier: Invalid specifier: 'lolwat'
     """
 
 
@@ -40,42 +53,39 @@ class BaseSpecifier(metaclass=abc.ABCMeta):
     @abc.abstractmethod
     def __str__(self) -> str:
         """
-        Returns the str representation of this Specifier like object. This
+        Returns the str representation of this Specifier-like object. This
         should be representative of the Specifier itself.
         """
 
     @abc.abstractmethod
     def __hash__(self) -> int:
         """
-        Returns a hash value for this Specifier like object.
+        Returns a hash value for this Specifier-like object.
         """
 
     @abc.abstractmethod
     def __eq__(self, other: object) -> bool:
         """
-        Returns a boolean representing whether or not the two Specifier like
+        Returns a boolean representing whether or not the two Specifier-like
         objects are equal.
-        """
 
-    @abc.abstractmethod
-    def __ne__(self, other: object) -> bool:
-        """
-        Returns a boolean representing whether or not the two Specifier like
-        objects are not equal.
+        :param other: The other object to check against.
         """
 
-    @abc.abstractproperty
+    @property
+    @abc.abstractmethod
     def prereleases(self) -> Optional[bool]:
-        """
-        Returns whether or not pre-releases as a whole are allowed by this
-        specifier.
+        """Whether or not pre-releases as a whole are allowed.
+
+        This can be set to either ``True`` or ``False`` to explicitly enable or disable
+        prereleases or it can be set to ``None`` (the default) to use default semantics.
         """
 
     @prereleases.setter
     def prereleases(self, value: bool) -> None:
-        """
-        Sets whether or not pre-releases as a whole are allowed by this
-        specifier.
+        """Setter for :attr:`prereleases`.
+
+        :param value: The value to set.
         """
 
     @abc.abstractmethod
@@ -86,238 +96,28 @@ def contains(self, item: str, prereleases: Optional[bool] = None) -> bool:
 
     @abc.abstractmethod
     def filter(
-        self, iterable: Iterable[VersionTypeVar], prereleases: Optional[bool] = None
-    ) -> Iterable[VersionTypeVar]:
+        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
+    ) -> Iterator[UnparsedVersionVar]:
         """
         Takes an iterable of items and filters them so that only items which
         are contained within this specifier are allowed in it.
         """
 
 
-class _IndividualSpecifier(BaseSpecifier):
-
-    _operators: Dict[str, str] = {}
-    _regex: Pattern[str]
-
-    def __init__(self, spec: str = "", prereleases: Optional[bool] = None) -> None:
-        match = self._regex.search(spec)
-        if not match:
-            raise InvalidSpecifier(f"Invalid specifier: '{spec}'")
-
-        self._spec: Tuple[str, str] = (
-            match.group("operator").strip(),
-            match.group("version").strip(),
-        )
-
-        # Store whether or not this Specifier should accept prereleases
-        self._prereleases = prereleases
-
-    def __repr__(self) -> str:
-        pre = (
-            f", prereleases={self.prereleases!r}"
-            if self._prereleases is not None
-            else ""
-        )
-
-        return "<{}({!r}{})>".format(self.__class__.__name__, str(self), pre)
-
-    def __str__(self) -> str:
-        return "{}{}".format(*self._spec)
-
-    @property
-    def _canonical_spec(self) -> Tuple[str, str]:
-        return self._spec[0], canonicalize_version(self._spec[1])
-
-    def __hash__(self) -> int:
-        return hash(self._canonical_spec)
-
-    def __eq__(self, other: object) -> bool:
-        if isinstance(other, str):
-            try:
-                other = self.__class__(str(other))
-            except InvalidSpecifier:
-                return NotImplemented
-        elif not isinstance(other, self.__class__):
-            return NotImplemented
-
-        return self._canonical_spec == other._canonical_spec
-
-    def __ne__(self, other: object) -> bool:
-        if isinstance(other, str):
-            try:
-                other = self.__class__(str(other))
-            except InvalidSpecifier:
-                return NotImplemented
-        elif not isinstance(other, self.__class__):
-            return NotImplemented
-
-        return self._spec != other._spec
-
-    def _get_operator(self, op: str) -> CallableOperator:
-        operator_callable: CallableOperator = getattr(
-            self, f"_compare_{self._operators[op]}"
-        )
-        return operator_callable
-
-    def _coerce_version(self, version: UnparsedVersion) -> ParsedVersion:
-        if not isinstance(version, (LegacyVersion, Version)):
-            version = parse(version)
-        return version
-
-    @property
-    def operator(self) -> str:
-        return self._spec[0]
-
-    @property
-    def version(self) -> str:
-        return self._spec[1]
-
-    @property
-    def prereleases(self) -> Optional[bool]:
-        return self._prereleases
-
-    @prereleases.setter
-    def prereleases(self, value: bool) -> None:
-        self._prereleases = value
-
-    def __contains__(self, item: str) -> bool:
-        return self.contains(item)
-
-    def contains(
-        self, item: UnparsedVersion, prereleases: Optional[bool] = None
-    ) -> bool:
-
-        # Determine if prereleases are to be allowed or not.
-        if prereleases is None:
-            prereleases = self.prereleases
-
-        # Normalize item to a Version or LegacyVersion, this allows us to have
-        # a shortcut for ``"2.0" in Specifier(">=2")
-        normalized_item = self._coerce_version(item)
-
-        # Determine if we should be supporting prereleases in this specifier
-        # or not, if we do not support prereleases than we can short circuit
-        # logic if this version is a prereleases.
-        if normalized_item.is_prerelease and not prereleases:
-            return False
-
-        # Actually do the comparison to determine if this item is contained
-        # within this Specifier or not.
-        operator_callable: CallableOperator = self._get_operator(self.operator)
-        return operator_callable(normalized_item, self.version)
-
-    def filter(
-        self, iterable: Iterable[VersionTypeVar], prereleases: Optional[bool] = None
-    ) -> Iterable[VersionTypeVar]:
-
-        yielded = False
-        found_prereleases = []
-
-        kw = {"prereleases": prereleases if prereleases is not None else True}
-
-        # Attempt to iterate over all the values in the iterable and if any of
-        # them match, yield them.
-        for version in iterable:
-            parsed_version = self._coerce_version(version)
-
-            if self.contains(parsed_version, **kw):
-                # If our version is a prerelease, and we were not set to allow
-                # prereleases, then we'll store it for later in case nothing
-                # else matches this specifier.
-                if parsed_version.is_prerelease and not (
-                    prereleases or self.prereleases
-                ):
-                    found_prereleases.append(version)
-                # Either this is not a prerelease, or we should have been
-                # accepting prereleases from the beginning.
-                else:
-                    yielded = True
-                    yield version
-
-        # Now that we've iterated over everything, determine if we've yielded
-        # any values, and if we have not and we have any prereleases stored up
-        # then we will go ahead and yield the prereleases.
-        if not yielded and found_prereleases:
-            for version in found_prereleases:
-                yield version
-
-
-class LegacySpecifier(_IndividualSpecifier):
-
-    _regex_str = r"""
-        (?P<operator>(==|!=|<=|>=|<|>))
-        \s*
-        (?P<version>
-            [^,;\s)]* # Since this is a "legacy" specifier, and the version
-                      # string can be just about anything, we match everything
-                      # except for whitespace, a semi-colon for marker support,
-                      # a closing paren since versions can be enclosed in
-                      # them, and a comma since it's a version separator.
-        )
-        """
-
-    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
-
-    _operators = {
-        "==": "equal",
-        "!=": "not_equal",
-        "<=": "less_than_equal",
-        ">=": "greater_than_equal",
-        "<": "less_than",
-        ">": "greater_than",
-    }
+class Specifier(BaseSpecifier):
+    """This class abstracts handling of version specifiers.
 
-    def __init__(self, spec: str = "", prereleases: Optional[bool] = None) -> None:
-        super().__init__(spec, prereleases)
+    .. tip::
 
-        warnings.warn(
-            "Creating a LegacyVersion has been deprecated and will be "
-            "removed in the next major release",
-            DeprecationWarning,
-        )
-
-    def _coerce_version(self, version: UnparsedVersion) -> LegacyVersion:
-        if not isinstance(version, LegacyVersion):
-            version = LegacyVersion(str(version))
-        return version
-
-    def _compare_equal(self, prospective: LegacyVersion, spec: str) -> bool:
-        return prospective == self._coerce_version(spec)
-
-    def _compare_not_equal(self, prospective: LegacyVersion, spec: str) -> bool:
-        return prospective != self._coerce_version(spec)
-
-    def _compare_less_than_equal(self, prospective: LegacyVersion, spec: str) -> bool:
-        return prospective <= self._coerce_version(spec)
-
-    def _compare_greater_than_equal(
-        self, prospective: LegacyVersion, spec: str
-    ) -> bool:
-        return prospective >= self._coerce_version(spec)
-
-    def _compare_less_than(self, prospective: LegacyVersion, spec: str) -> bool:
-        return prospective < self._coerce_version(spec)
-
-    def _compare_greater_than(self, prospective: LegacyVersion, spec: str) -> bool:
-        return prospective > self._coerce_version(spec)
-
-
-def _require_version_compare(
-    fn: Callable[["Specifier", ParsedVersion, str], bool]
-) -> Callable[["Specifier", ParsedVersion, str], bool]:
-    @functools.wraps(fn)
-    def wrapped(self: "Specifier", prospective: ParsedVersion, spec: str) -> bool:
-        if not isinstance(prospective, Version):
-            return False
-        return fn(self, prospective, spec)
-
-    return wrapped
-
-
-class Specifier(_IndividualSpecifier):
+        It is generally not required to instantiate this manually. You should instead
+        prefer to work with :class:`SpecifierSet` instead, which can parse
+        comma-separated version specifiers (which is what package metadata contains).
+    """
 
-    _regex_str = r"""
+    _operator_regex_str = r"""
         (?P<operator>(~=|==|!=|<=|>=|<|>|===))
+        """
+    _version_regex_str = r"""
         (?P<version>
             (?:
                 # The identity operators allow for an escape hatch that will
@@ -327,8 +127,10 @@ class Specifier(_IndividualSpecifier):
                 # but included entirely as an escape hatch.
                 (?<====)  # Only match for the identity operator
                 \s*
-                [^\s]*    # We just match everything, except for whitespace
-                          # since we are only testing for strict identity.
+                [^\s;)]*  # The arbitrary version can be just about anything,
+                          # we match everything except for whitespace, a
+                          # semi-colon for marker support, and a closing paren
+                          # since versions can be enclosed in them.
             )
             |
             (?:
@@ -341,23 +143,23 @@ class Specifier(_IndividualSpecifier):
                 v?
                 (?:[0-9]+!)?          # epoch
                 [0-9]+(?:\.[0-9]+)*   # release
-                (?:                   # pre release
-                    [-_\.]?
-                    (a|b|c|rc|alpha|beta|pre|preview)
-                    [-_\.]?
-                    [0-9]*
-                )?
-                (?:                   # post release
-                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
-                )?
 
-                # You cannot use a wild card and a dev or local version
-                # together so group them with a | and make them optional.
+                # You cannot use a wild card and a pre-release, post-release, a dev or
+                # local version together so group them with a | and make them optional.
                 (?:
+                    \.\*  # Wild card syntax of .*
+                    |
+                    (?:                                  # pre release
+                        [-_\.]?
+                        (alpha|beta|preview|pre|a|b|c|rc)
+                        [-_\.]?
+                        [0-9]*
+                    )?
+                    (?:                                  # post release
+                        (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                    )?
                     (?:[-_\.]?dev[-_\.]?[0-9]*)?         # dev release
                     (?:\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*)? # local
-                    |
-                    \.\*  # Wild card syntax of .*
                 )?
             )
             |
@@ -372,7 +174,7 @@ class Specifier(_IndividualSpecifier):
                 [0-9]+(?:\.[0-9]+)+   # release  (We have a + instead of a *)
                 (?:                   # pre release
                     [-_\.]?
-                    (a|b|c|rc|alpha|beta|pre|preview)
+                    (alpha|beta|preview|pre|a|b|c|rc)
                     [-_\.]?
                     [0-9]*
                 )?
@@ -397,7 +199,7 @@ class Specifier(_IndividualSpecifier):
                 [0-9]+(?:\.[0-9]+)*   # release
                 (?:                   # pre release
                     [-_\.]?
-                    (a|b|c|rc|alpha|beta|pre|preview)
+                    (alpha|beta|preview|pre|a|b|c|rc)
                     [-_\.]?
                     [0-9]*
                 )?
@@ -409,7 +211,10 @@ class Specifier(_IndividualSpecifier):
         )
         """
 
-    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+    _regex = re.compile(
+        r"^\s*" + _operator_regex_str + _version_regex_str + r"\s*$",
+        re.VERBOSE | re.IGNORECASE,
+    )
 
     _operators = {
         "~=": "compatible",
@@ -422,8 +227,153 @@ class Specifier(_IndividualSpecifier):
         "===": "arbitrary",
     }
 
-    @_require_version_compare
-    def _compare_compatible(self, prospective: ParsedVersion, spec: str) -> bool:
+    def __init__(self, spec: str = "", prereleases: Optional[bool] = None) -> None:
+        """Initialize a Specifier instance.
+
+        :param spec:
+            The string representation of a specifier which will be parsed and
+            normalized before use.
+        :param prereleases:
+            This tells the specifier if it should accept prerelease versions if
+            applicable or not. The default of ``None`` will autodetect it from the
+            given specifiers.
+        :raises InvalidSpecifier:
+            If the given specifier is invalid (i.e. bad syntax).
+        """
+        match = self._regex.search(spec)
+        if not match:
+            raise InvalidSpecifier(f"Invalid specifier: '{spec}'")
+
+        self._spec: Tuple[str, str] = (
+            match.group("operator").strip(),
+            match.group("version").strip(),
+        )
+
+        # Store whether or not this Specifier should accept prereleases
+        self._prereleases = prereleases
+
+    # https://github.com/python/mypy/pull/13475#pullrequestreview-1079784515
+    @property  # type: ignore[override]
+    def prereleases(self) -> bool:
+        # If there is an explicit prereleases set for this, then we'll just
+        # blindly use that.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # Look at all of our specifiers and determine if they are inclusive
+        # operators, and if they are if they are including an explicit
+        # prerelease.
+        operator, version = self._spec
+        if operator in ["==", ">=", "<=", "~=", "==="]:
+            # The == specifier can include a trailing .*, if it does we
+            # want to remove before parsing.
+            if operator == "==" and version.endswith(".*"):
+                version = version[:-2]
+
+            # Parse the version, and if it is a pre-release than this
+            # specifier allows pre-releases.
+            if Version(version).is_prerelease:
+                return True
+
+        return False
+
+    @prereleases.setter
+    def prereleases(self, value: bool) -> None:
+        self._prereleases = value
+
+    @property
+    def operator(self) -> str:
+        """The operator of this specifier.
+
+        >>> Specifier("==1.2.3").operator
+        '=='
+        """
+        return self._spec[0]
+
+    @property
+    def version(self) -> str:
+        """The version of this specifier.
+
+        >>> Specifier("==1.2.3").version
+        '1.2.3'
+        """
+        return self._spec[1]
+
+    def __repr__(self) -> str:
+        """A representation of the Specifier that shows all internal state.
+
+        >>> Specifier('>=1.0.0')
+        <Specifier('>=1.0.0')>
+        >>> Specifier('>=1.0.0', prereleases=False)
+        <Specifier('>=1.0.0', prereleases=False)>
+        >>> Specifier('>=1.0.0', prereleases=True)
+        <Specifier('>=1.0.0', prereleases=True)>
+        """
+        pre = (
+            f", prereleases={self.prereleases!r}"
+            if self._prereleases is not None
+            else ""
+        )
+
+        return f"<{self.__class__.__name__}({str(self)!r}{pre})>"
+
+    def __str__(self) -> str:
+        """A string representation of the Specifier that can be round-tripped.
+
+        >>> str(Specifier('>=1.0.0'))
+        '>=1.0.0'
+        >>> str(Specifier('>=1.0.0', prereleases=False))
+        '>=1.0.0'
+        """
+        return "{}{}".format(*self._spec)
+
+    @property
+    def _canonical_spec(self) -> Tuple[str, str]:
+        canonical_version = canonicalize_version(
+            self._spec[1],
+            strip_trailing_zero=(self._spec[0] != "~="),
+        )
+        return self._spec[0], canonical_version
+
+    def __hash__(self) -> int:
+        return hash(self._canonical_spec)
+
+    def __eq__(self, other: object) -> bool:
+        """Whether or not the two Specifier-like objects are equal.
+
+        :param other: The other object to check against.
+
+        The value of :attr:`prereleases` is ignored.
+
+        >>> Specifier("==1.2.3") == Specifier("== 1.2.3.0")
+        True
+        >>> (Specifier("==1.2.3", prereleases=False) ==
+        ...  Specifier("==1.2.3", prereleases=True))
+        True
+        >>> Specifier("==1.2.3") == "==1.2.3"
+        True
+        >>> Specifier("==1.2.3") == Specifier("==1.2.4")
+        False
+        >>> Specifier("==1.2.3") == Specifier("~=1.2.3")
+        False
+        """
+        if isinstance(other, str):
+            try:
+                other = self.__class__(str(other))
+            except InvalidSpecifier:
+                return NotImplemented
+        elif not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._canonical_spec == other._canonical_spec
+
+    def _get_operator(self, op: str) -> CallableOperator:
+        operator_callable: CallableOperator = getattr(
+            self, f"_compare_{self._operators[op]}"
+        )
+        return operator_callable
+
+    def _compare_compatible(self, prospective: Version, spec: str) -> bool:
 
         # Compatible releases have an equivalent combination of >= and ==. That
         # is that ~=2.2 is equivalent to >=2.2,==2.*. This allows us to
@@ -444,34 +394,35 @@ def _compare_compatible(self, prospective: ParsedVersion, spec: str) -> bool:
             prospective, prefix
         )
 
-    @_require_version_compare
-    def _compare_equal(self, prospective: ParsedVersion, spec: str) -> bool:
+    def _compare_equal(self, prospective: Version, spec: str) -> bool:
 
         # We need special logic to handle prefix matching
         if spec.endswith(".*"):
             # In the case of prefix matching we want to ignore local segment.
-            prospective = Version(prospective.public)
+            normalized_prospective = canonicalize_version(
+                prospective.public, strip_trailing_zero=False
+            )
+            # Get the normalized version string ignoring the trailing .*
+            normalized_spec = canonicalize_version(spec[:-2], strip_trailing_zero=False)
             # Split the spec out by dots, and pretend that there is an implicit
             # dot in between a release segment and a pre-release segment.
-            split_spec = _version_split(spec[:-2])  # Remove the trailing .*
+            split_spec = _version_split(normalized_spec)
 
             # Split the prospective version out by dots, and pretend that there
             # is an implicit dot in between a release segment and a pre-release
             # segment.
-            split_prospective = _version_split(str(prospective))
+            split_prospective = _version_split(normalized_prospective)
+
+            # 0-pad the prospective version before shortening it to get the correct
+            # shortened version.
+            padded_prospective, _ = _pad_version(split_prospective, split_spec)
 
             # Shorten the prospective version to be the same length as the spec
             # so that we can determine if the specifier is a prefix of the
             # prospective version or not.
-            shortened_prospective = split_prospective[: len(split_spec)]
-
-            # Pad out our two sides with zeros so that they both equal the same
-            # length.
-            padded_spec, padded_prospective = _pad_version(
-                split_spec, shortened_prospective
-            )
+            shortened_prospective = padded_prospective[: len(split_spec)]
 
-            return padded_prospective == padded_spec
+            return shortened_prospective == split_spec
         else:
             # Convert our spec string into a Version
             spec_version = Version(spec)
@@ -484,30 +435,24 @@ def _compare_equal(self, prospective: ParsedVersion, spec: str) -> bool:
 
             return prospective == spec_version
 
-    @_require_version_compare
-    def _compare_not_equal(self, prospective: ParsedVersion, spec: str) -> bool:
+    def _compare_not_equal(self, prospective: Version, spec: str) -> bool:
         return not self._compare_equal(prospective, spec)
 
-    @_require_version_compare
-    def _compare_less_than_equal(self, prospective: ParsedVersion, spec: str) -> bool:
+    def _compare_less_than_equal(self, prospective: Version, spec: str) -> bool:
 
         # NB: Local version identifiers are NOT permitted in the version
         # specifier, so local version labels can be universally removed from
         # the prospective version.
         return Version(prospective.public) <= Version(spec)
 
-    @_require_version_compare
-    def _compare_greater_than_equal(
-        self, prospective: ParsedVersion, spec: str
-    ) -> bool:
+    def _compare_greater_than_equal(self, prospective: Version, spec: str) -> bool:
 
         # NB: Local version identifiers are NOT permitted in the version
         # specifier, so local version labels can be universally removed from
         # the prospective version.
         return Version(prospective.public) >= Version(spec)
 
-    @_require_version_compare
-    def _compare_less_than(self, prospective: ParsedVersion, spec_str: str) -> bool:
+    def _compare_less_than(self, prospective: Version, spec_str: str) -> bool:
 
         # Convert our spec to a Version instance, since we'll want to work with
         # it as a version.
@@ -532,8 +477,7 @@ def _compare_less_than(self, prospective: ParsedVersion, spec_str: str) -> bool:
         # version in the spec.
         return True
 
-    @_require_version_compare
-    def _compare_greater_than(self, prospective: ParsedVersion, spec_str: str) -> bool:
+    def _compare_greater_than(self, prospective: Version, spec_str: str) -> bool:
 
         # Convert our spec to a Version instance, since we'll want to work with
         # it as a version.
@@ -567,34 +511,133 @@ def _compare_greater_than(self, prospective: ParsedVersion, spec_str: str) -> bo
     def _compare_arbitrary(self, prospective: Version, spec: str) -> bool:
         return str(prospective).lower() == str(spec).lower()
 
-    @property
-    def prereleases(self) -> bool:
+    def __contains__(self, item: Union[str, Version]) -> bool:
+        """Return whether or not the item is contained in this specifier.
 
-        # If there is an explicit prereleases set for this, then we'll just
-        # blindly use that.
-        if self._prereleases is not None:
-            return self._prereleases
+        :param item: The item to check for.
 
-        # Look at all of our specifiers and determine if they are inclusive
-        # operators, and if they are if they are including an explicit
-        # prerelease.
-        operator, version = self._spec
-        if operator in ["==", ">=", "<=", "~=", "==="]:
-            # The == specifier can include a trailing .*, if it does we
-            # want to remove before parsing.
-            if operator == "==" and version.endswith(".*"):
-                version = version[:-2]
+        This is used for the ``in`` operator and behaves the same as
+        :meth:`contains` with no ``prereleases`` argument passed.
 
-            # Parse the version, and if it is a pre-release than this
-            # specifier allows pre-releases.
-            if parse(version).is_prerelease:
-                return True
+        >>> "1.2.3" in Specifier(">=1.2.3")
+        True
+        >>> Version("1.2.3") in Specifier(">=1.2.3")
+        True
+        >>> "1.0.0" in Specifier(">=1.2.3")
+        False
+        >>> "1.3.0a1" in Specifier(">=1.2.3")
+        False
+        >>> "1.3.0a1" in Specifier(">=1.2.3", prereleases=True)
+        True
+        """
+        return self.contains(item)
 
-        return False
+    def contains(
+        self, item: UnparsedVersion, prereleases: Optional[bool] = None
+    ) -> bool:
+        """Return whether or not the item is contained in this specifier.
+
+        :param item:
+            The item to check for, which can be a version string or a
+            :class:`Version` instance.
+        :param prereleases:
+            Whether or not to match prereleases with this Specifier. If set to
+            ``None`` (the default), it uses :attr:`prereleases` to determine
+            whether or not prereleases are allowed.
+
+        >>> Specifier(">=1.2.3").contains("1.2.3")
+        True
+        >>> Specifier(">=1.2.3").contains(Version("1.2.3"))
+        True
+        >>> Specifier(">=1.2.3").contains("1.0.0")
+        False
+        >>> Specifier(">=1.2.3").contains("1.3.0a1")
+        False
+        >>> Specifier(">=1.2.3", prereleases=True).contains("1.3.0a1")
+        True
+        >>> Specifier(">=1.2.3").contains("1.3.0a1", prereleases=True)
+        True
+        """
 
-    @prereleases.setter
-    def prereleases(self, value: bool) -> None:
-        self._prereleases = value
+        # Determine if prereleases are to be allowed or not.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # Normalize item to a Version, this allows us to have a shortcut for
+        # "2.0" in Specifier(">=2")
+        normalized_item = _coerce_version(item)
+
+        # Determine if we should be supporting prereleases in this specifier
+        # or not, if we do not support prereleases than we can short circuit
+        # logic if this version is a prereleases.
+        if normalized_item.is_prerelease and not prereleases:
+            return False
+
+        # Actually do the comparison to determine if this item is contained
+        # within this Specifier or not.
+        operator_callable: CallableOperator = self._get_operator(self.operator)
+        return operator_callable(normalized_item, self.version)
+
+    def filter(
+        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
+    ) -> Iterator[UnparsedVersionVar]:
+        """Filter items in the given iterable, that match the specifier.
+
+        :param iterable:
+            An iterable that can contain version strings and :class:`Version` instances.
+            The items in the iterable will be filtered according to the specifier.
+        :param prereleases:
+            Whether or not to allow prereleases in the returned iterator. If set to
+            ``None`` (the default), it will be intelligently decide whether to allow
+            prereleases or not (based on the :attr:`prereleases` attribute, and
+            whether the only versions matching are prereleases).
+
+        This method is smarter than just ``filter(Specifier().contains, [...])``
+        because it implements the rule from :pep:`440` that a prerelease item
+        SHOULD be accepted if no other versions match the given specifier.
+
+        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.3", "1.5a1"]))
+        ['1.3']
+        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.2.3", "1.3", Version("1.4")]))
+        ['1.2.3', '1.3', <Version('1.4')>]
+        >>> list(Specifier(">=1.2.3").filter(["1.2", "1.5a1"]))
+        ['1.5a1']
+        >>> list(Specifier(">=1.2.3").filter(["1.3", "1.5a1"], prereleases=True))
+        ['1.3', '1.5a1']
+        >>> list(Specifier(">=1.2.3", prereleases=True).filter(["1.3", "1.5a1"]))
+        ['1.3', '1.5a1']
+        """
+
+        yielded = False
+        found_prereleases = []
+
+        kw = {"prereleases": prereleases if prereleases is not None else True}
+
+        # Attempt to iterate over all the values in the iterable and if any of
+        # them match, yield them.
+        for version in iterable:
+            parsed_version = _coerce_version(version)
+
+            if self.contains(parsed_version, **kw):
+                # If our version is a prerelease, and we were not set to allow
+                # prereleases, then we'll store it for later in case nothing
+                # else matches this specifier.
+                if parsed_version.is_prerelease and not (
+                    prereleases or self.prereleases
+                ):
+                    found_prereleases.append(version)
+                # Either this is not a prerelease, or we should have been
+                # accepting prereleases from the beginning.
+                else:
+                    yielded = True
+                    yield version
+
+        # Now that we've iterated over everything, determine if we've yielded
+        # any values, and if we have not and we have any prereleases stored up
+        # then we will go ahead and yield the prereleases.
+        if not yielded and found_prereleases:
+            for version in found_prereleases:
+                yield version
 
 
 _prefix_regex = re.compile(r"^([0-9]+)((?:a|b|c|rc)[0-9]+)$")
@@ -636,22 +679,39 @@ def _pad_version(left: List[str], right: List[str]) -> Tuple[List[str], List[str
 
 
 class SpecifierSet(BaseSpecifier):
+    """This class abstracts handling of a set of version specifiers.
+
+    It can be passed a single specifier (``>=3.0``), a comma-separated list of
+    specifiers (``>=3.0,!=3.1``), or no specifier at all.
+    """
+
     def __init__(
         self, specifiers: str = "", prereleases: Optional[bool] = None
     ) -> None:
+        """Initialize a SpecifierSet instance.
+
+        :param specifiers:
+            The string representation of a specifier or a comma-separated list of
+            specifiers which will be parsed and normalized before use.
+        :param prereleases:
+            This tells the SpecifierSet if it should accept prerelease versions if
+            applicable or not. The default of ``None`` will autodetect it from the
+            given specifiers.
+
+        :raises InvalidSpecifier:
+            If the given ``specifiers`` are not parseable than this exception will be
+            raised.
+        """
 
-        # Split on , to break each individual specifier into it's own item, and
+        # Split on `,` to break each individual specifier into it's own item, and
         # strip each item to remove leading/trailing whitespace.
         split_specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]
 
         # Parsed each individual specifier, attempting first to make it a
-        # Specifier and falling back to a LegacySpecifier.
-        parsed: Set[_IndividualSpecifier] = set()
+        # Specifier.
+        parsed: Set[Specifier] = set()
         for specifier in split_specifiers:
-            try:
-                parsed.add(Specifier(specifier))
-            except InvalidSpecifier:
-                parsed.add(LegacySpecifier(specifier))
+            parsed.add(Specifier(specifier))
 
         # Turn our parsed specifiers into a frozen set and save them for later.
         self._specs = frozenset(parsed)
@@ -660,22 +720,74 @@ def __init__(
         # we accept prereleases or not.
         self._prereleases = prereleases
 
+    @property
+    def prereleases(self) -> Optional[bool]:
+        # If we have been given an explicit prerelease modifier, then we'll
+        # pass that through here.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # If we don't have any specifiers, and we don't have a forced value,
+        # then we'll just return None since we don't know if this should have
+        # pre-releases or not.
+        if not self._specs:
+            return None
+
+        # Otherwise we'll see if any of the given specifiers accept
+        # prereleases, if any of them do we'll return True, otherwise False.
+        return any(s.prereleases for s in self._specs)
+
+    @prereleases.setter
+    def prereleases(self, value: bool) -> None:
+        self._prereleases = value
+
     def __repr__(self) -> str:
+        """A representation of the specifier set that shows all internal state.
+
+        Note that the ordering of the individual specifiers within the set may not
+        match the input string.
+
+        >>> SpecifierSet('>=1.0.0,!=2.0.0')
+        <SpecifierSet('!=2.0.0,>=1.0.0')>
+        >>> SpecifierSet('>=1.0.0,!=2.0.0', prereleases=False)
+        <SpecifierSet('!=2.0.0,>=1.0.0', prereleases=False)>
+        >>> SpecifierSet('>=1.0.0,!=2.0.0', prereleases=True)
+        <SpecifierSet('!=2.0.0,>=1.0.0', prereleases=True)>
+        """
         pre = (
             f", prereleases={self.prereleases!r}"
             if self._prereleases is not None
             else ""
         )
 
-        return "<SpecifierSet({!r}{})>".format(str(self), pre)
+        return f"<SpecifierSet({str(self)!r}{pre})>"
 
     def __str__(self) -> str:
+        """A string representation of the specifier set that can be round-tripped.
+
+        Note that the ordering of the individual specifiers within the set may not
+        match the input string.
+
+        >>> str(SpecifierSet(">=1.0.0,!=1.0.1"))
+        '!=1.0.1,>=1.0.0'
+        >>> str(SpecifierSet(">=1.0.0,!=1.0.1", prereleases=False))
+        '!=1.0.1,>=1.0.0'
+        """
         return ",".join(sorted(str(s) for s in self._specs))
 
     def __hash__(self) -> int:
         return hash(self._specs)
 
     def __and__(self, other: Union["SpecifierSet", str]) -> "SpecifierSet":
+        """Return a SpecifierSet which is a combination of the two sets.
+
+        :param other: The other object to combine with.
+
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") & '<=2.0.0,!=2.0.1'
+        <SpecifierSet('!=1.0.1,!=2.0.1,<=2.0.0,>=1.0.0')>
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") & SpecifierSet('<=2.0.0,!=2.0.1')
+        <SpecifierSet('!=1.0.1,!=2.0.1,<=2.0.0,>=1.0.0')>
+        """
         if isinstance(other, str):
             other = SpecifierSet(other)
         elif not isinstance(other, SpecifierSet):
@@ -699,59 +811,98 @@ def __and__(self, other: Union["SpecifierSet", str]) -> "SpecifierSet":
         return specifier
 
     def __eq__(self, other: object) -> bool:
-        if isinstance(other, (str, _IndividualSpecifier)):
+        """Whether or not the two SpecifierSet-like objects are equal.
+
+        :param other: The other object to check against.
+
+        The value of :attr:`prereleases` is ignored.
+
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0,!=1.0.1")
+        True
+        >>> (SpecifierSet(">=1.0.0,!=1.0.1", prereleases=False) ==
+        ...  SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True))
+        True
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") == ">=1.0.0,!=1.0.1"
+        True
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0")
+        False
+        >>> SpecifierSet(">=1.0.0,!=1.0.1") == SpecifierSet(">=1.0.0,!=1.0.2")
+        False
+        """
+        if isinstance(other, (str, Specifier)):
             other = SpecifierSet(str(other))
         elif not isinstance(other, SpecifierSet):
             return NotImplemented
 
         return self._specs == other._specs
 
-    def __ne__(self, other: object) -> bool:
-        if isinstance(other, (str, _IndividualSpecifier)):
-            other = SpecifierSet(str(other))
-        elif not isinstance(other, SpecifierSet):
-            return NotImplemented
-
-        return self._specs != other._specs
-
     def __len__(self) -> int:
+        """Returns the number of specifiers in this specifier set."""
         return len(self._specs)
 
-    def __iter__(self) -> Iterator[_IndividualSpecifier]:
-        return iter(self._specs)
-
-    @property
-    def prereleases(self) -> Optional[bool]:
-
-        # If we have been given an explicit prerelease modifier, then we'll
-        # pass that through here.
-        if self._prereleases is not None:
-            return self._prereleases
-
-        # If we don't have any specifiers, and we don't have a forced value,
-        # then we'll just return None since we don't know if this should have
-        # pre-releases or not.
-        if not self._specs:
-            return None
-
-        # Otherwise we'll see if any of the given specifiers accept
-        # prereleases, if any of them do we'll return True, otherwise False.
-        return any(s.prereleases for s in self._specs)
+    def __iter__(self) -> Iterator[Specifier]:
+        """
+        Returns an iterator over all the underlying :class:`Specifier` instances
+        in this specifier set.
 
-    @prereleases.setter
-    def prereleases(self, value: bool) -> None:
-        self._prereleases = value
+        >>> sorted(SpecifierSet(">=1.0.0,!=1.0.1"), key=str)
+        [<Specifier('!=1.0.1')>, <Specifier('>=1.0.0')>]
+        """
+        return iter(self._specs)
 
     def __contains__(self, item: UnparsedVersion) -> bool:
+        """Return whether or not the item is contained in this specifier.
+
+        :param item: The item to check for.
+
+        This is used for the ``in`` operator and behaves the same as
+        :meth:`contains` with no ``prereleases`` argument passed.
+
+        >>> "1.2.3" in SpecifierSet(">=1.0.0,!=1.0.1")
+        True
+        >>> Version("1.2.3") in SpecifierSet(">=1.0.0,!=1.0.1")
+        True
+        >>> "1.0.1" in SpecifierSet(">=1.0.0,!=1.0.1")
+        False
+        >>> "1.3.0a1" in SpecifierSet(">=1.0.0,!=1.0.1")
+        False
+        >>> "1.3.0a1" in SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True)
+        True
+        """
         return self.contains(item)
 
     def contains(
-        self, item: UnparsedVersion, prereleases: Optional[bool] = None
+        self,
+        item: UnparsedVersion,
+        prereleases: Optional[bool] = None,
+        installed: Optional[bool] = None,
     ) -> bool:
-
-        # Ensure that our item is a Version or LegacyVersion instance.
-        if not isinstance(item, (LegacyVersion, Version)):
-            item = parse(item)
+        """Return whether or not the item is contained in this SpecifierSet.
+
+        :param item:
+            The item to check for, which can be a version string or a
+            :class:`Version` instance.
+        :param prereleases:
+            Whether or not to match prereleases with this SpecifierSet. If set to
+            ``None`` (the default), it uses :attr:`prereleases` to determine
+            whether or not prereleases are allowed.
+
+        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.2.3")
+        True
+        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains(Version("1.2.3"))
+        True
+        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.0.1")
+        False
+        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.3.0a1")
+        False
+        >>> SpecifierSet(">=1.0.0,!=1.0.1", prereleases=True).contains("1.3.0a1")
+        True
+        >>> SpecifierSet(">=1.0.0,!=1.0.1").contains("1.3.0a1", prereleases=True)
+        True
+        """
+        # Ensure that our item is a Version instance.
+        if not isinstance(item, Version):
+            item = Version(item)
 
         # Determine if we're forcing a prerelease or not, if we're not forcing
         # one for this particular filter call, then we'll use whatever the
@@ -768,6 +919,9 @@ def contains(
         if not prereleases and item.is_prerelease:
             return False
 
+        if installed and item.is_prerelease:
+            item = Version(item.base_version)
+
         # We simply dispatch to the underlying specs here to make sure that the
         # given version is contained within all of them.
         # Note: This use of all() here means that an empty set of specifiers
@@ -775,9 +929,46 @@ def contains(
         return all(s.contains(item, prereleases=prereleases) for s in self._specs)
 
     def filter(
-        self, iterable: Iterable[VersionTypeVar], prereleases: Optional[bool] = None
-    ) -> Iterable[VersionTypeVar]:
-
+        self, iterable: Iterable[UnparsedVersionVar], prereleases: Optional[bool] = None
+    ) -> Iterator[UnparsedVersionVar]:
+        """Filter items in the given iterable, that match the specifiers in this set.
+
+        :param iterable:
+            An iterable that can contain version strings and :class:`Version` instances.
+            The items in the iterable will be filtered according to the specifier.
+        :param prereleases:
+            Whether or not to allow prereleases in the returned iterator. If set to
+            ``None`` (the default), it will be intelligently decide whether to allow
+            prereleases or not (based on the :attr:`prereleases` attribute, and
+            whether the only versions matching are prereleases).
+
+        This method is smarter than just ``filter(SpecifierSet(...).contains, [...])``
+        because it implements the rule from :pep:`440` that a prerelease item
+        SHOULD be accepted if no other versions match the given specifier.
+
+        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.3", "1.5a1"]))
+        ['1.3']
+        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.3", Version("1.4")]))
+        ['1.3', <Version('1.4')>]
+        >>> list(SpecifierSet(">=1.2.3").filter(["1.2", "1.5a1"]))
+        []
+        >>> list(SpecifierSet(">=1.2.3").filter(["1.3", "1.5a1"], prereleases=True))
+        ['1.3', '1.5a1']
+        >>> list(SpecifierSet(">=1.2.3", prereleases=True).filter(["1.3", "1.5a1"]))
+        ['1.3', '1.5a1']
+
+        An "empty" SpecifierSet will filter items based on the presence of prerelease
+        versions in the set.
+
+        >>> list(SpecifierSet("").filter(["1.3", "1.5a1"]))
+        ['1.3']
+        >>> list(SpecifierSet("").filter(["1.5a1"]))
+        ['1.5a1']
+        >>> list(SpecifierSet("", prereleases=True).filter(["1.3", "1.5a1"]))
+        ['1.3', '1.5a1']
+        >>> list(SpecifierSet("").filter(["1.3", "1.5a1"], prereleases=True))
+        ['1.3', '1.5a1']
+        """
         # Determine if we're forcing a prerelease or not, if we're not forcing
         # one for this particular filter call, then we'll use whatever the
         # SpecifierSet thinks for whether or not we should support prereleases.
@@ -790,27 +981,16 @@ def filter(
         if self._specs:
             for spec in self._specs:
                 iterable = spec.filter(iterable, prereleases=bool(prereleases))
-            return iterable
+            return iter(iterable)
         # If we do not have any specifiers, then we need to have a rough filter
         # which will filter out any pre-releases, unless there are no final
-        # releases, and which will filter out LegacyVersion in general.
+        # releases.
         else:
-            filtered: List[VersionTypeVar] = []
-            found_prereleases: List[VersionTypeVar] = []
-
-            item: UnparsedVersion
-            parsed_version: Union[Version, LegacyVersion]
+            filtered: List[UnparsedVersionVar] = []
+            found_prereleases: List[UnparsedVersionVar] = []
 
             for item in iterable:
-                # Ensure that we some kind of Version class for this item.
-                if not isinstance(item, (LegacyVersion, Version)):
-                    parsed_version = parse(item)
-                else:
-                    parsed_version = item
-
-                # Filter out any item which is parsed as a LegacyVersion
-                if isinstance(parsed_version, LegacyVersion):
-                    continue
+                parsed_version = _coerce_version(item)
 
                 # Store any item which is a pre-release for later unless we've
                 # already found a final version or we are accepting prereleases
@@ -823,6 +1003,6 @@ def filter(
             # If we've found no items except for pre-releases, then we'll go
             # ahead and use the pre-releases
             if not filtered and found_prereleases and prereleases is None:
-                return found_prereleases
+                return iter(found_prereleases)
 
-            return filtered
+            return iter(filtered)
diff --git a/pip_api/_vendor/packaging/tags.py b/pip_api/_vendor/packaging/tags.py
index 82a47cd..37f33b1 100644
--- a/pip_api/_vendor/packaging/tags.py
+++ b/pip_api/_vendor/packaging/tags.py
@@ -4,6 +4,8 @@
 
 import logging
 import platform
+import struct
+import subprocess
 import sys
 import sysconfig
 from importlib.machinery import EXTENSION_SUFFIXES
@@ -36,7 +38,7 @@
 }
 
 
-_32_BIT_INTERPRETER = sys.maxsize <= 2 ** 32
+_32_BIT_INTERPRETER = struct.calcsize("P") == 4
 
 
 class Tag:
@@ -90,7 +92,7 @@ def __str__(self) -> str:
         return f"{self._interpreter}-{self._abi}-{self._platform}"
 
     def __repr__(self) -> str:
-        return "<{self} @ {self_id}>".format(self=self, self_id=id(self))
+        return f"<{self} @ {id(self)}>"
 
 
 def parse_tag(tag: str) -> FrozenSet[Tag]:
@@ -110,7 +112,7 @@ def parse_tag(tag: str) -> FrozenSet[Tag]:
 
 
 def _get_config_var(name: str, warn: bool = False) -> Union[int, str, None]:
-    value = sysconfig.get_config_var(name)
+    value: Union[int, str, None] = sysconfig.get_config_var(name)
     if value is None and warn:
         logger.debug(
             "Config variable '%s' is unset, Python ABI tag may be incorrect", name
@@ -119,7 +121,7 @@ def _get_config_var(name: str, warn: bool = False) -> Union[int, str, None]:
 
 
 def _normalize_string(string: str) -> str:
-    return string.replace(".", "_").replace("-", "_")
+    return string.replace(".", "_").replace("-", "_").replace(" ", "_")
 
 
 def _abi3_applies(python_version: PythonVersion) -> bool:
@@ -192,7 +194,7 @@ def cpython_tags(
     if not python_version:
         python_version = sys.version_info[:2]
 
-    interpreter = "cp{}".format(_version_nodot(python_version[:2]))
+    interpreter = f"cp{_version_nodot(python_version[:2])}"
 
     if abis is None:
         if len(python_version) > 1:
@@ -207,7 +209,7 @@ def cpython_tags(
         except ValueError:
             pass
 
-    platforms = list(platforms or _platform_tags())
+    platforms = list(platforms or platform_tags())
     for abi in abis:
         for platform_ in platforms:
             yield Tag(interpreter, abi, platform_)
@@ -224,10 +226,45 @@ def cpython_tags(
                 yield Tag(interpreter, "abi3", platform_)
 
 
-def _generic_abi() -> Iterator[str]:
-    abi = sysconfig.get_config_var("SOABI")
-    if abi:
-        yield _normalize_string(abi)
+def _generic_abi() -> List[str]:
+    """
+    Return the ABI tag based on EXT_SUFFIX.
+    """
+    # The following are examples of `EXT_SUFFIX`.
+    # We want to keep the parts which are related to the ABI and remove the
+    # parts which are related to the platform:
+    # - linux:   '.cpython-310-x86_64-linux-gnu.so' => cp310
+    # - mac:     '.cpython-310-darwin.so'           => cp310
+    # - win:     '.cp310-win_amd64.pyd'             => cp310
+    # - win:     '.pyd'                             => cp37 (uses _cpython_abis())
+    # - pypy:    '.pypy38-pp73-x86_64-linux-gnu.so' => pypy38_pp73
+    # - graalpy: '.graalpy-38-native-x86_64-darwin.dylib'
+    #                                               => graalpy_38_native
+
+    ext_suffix = _get_config_var("EXT_SUFFIX", warn=True)
+    if not isinstance(ext_suffix, str) or ext_suffix[0] != ".":
+        raise SystemError("invalid sysconfig.get_config_var('EXT_SUFFIX')")
+    parts = ext_suffix.split(".")
+    if len(parts) < 3:
+        # CPython3.7 and earlier uses ".pyd" on Windows.
+        return _cpython_abis(sys.version_info[:2])
+    soabi = parts[1]
+    if soabi.startswith("cpython"):
+        # non-windows
+        abi = "cp" + soabi.split("-")[1]
+    elif soabi.startswith("cp"):
+        # windows
+        abi = soabi.split("-")[0]
+    elif soabi.startswith("pypy"):
+        abi = "-".join(soabi.split("-")[:2])
+    elif soabi.startswith("graalpy"):
+        abi = "-".join(soabi.split("-")[:3])
+    elif soabi:
+        # pyston, ironpython, others?
+        abi = soabi
+    else:
+        return []
+    return [_normalize_string(abi)]
 
 
 def generic_tags(
@@ -251,8 +288,9 @@ def generic_tags(
         interpreter = "".join([interp_name, interp_version])
     if abis is None:
         abis = _generic_abi()
-    platforms = list(platforms or _platform_tags())
-    abis = list(abis)
+    else:
+        abis = list(abis)
+    platforms = list(platforms or platform_tags())
     if "none" not in abis:
         abis.append("none")
     for abi in abis:
@@ -268,11 +306,11 @@ def _py_interpreter_range(py_version: PythonVersion) -> Iterator[str]:
     all previous versions of that major version.
     """
     if len(py_version) > 1:
-        yield "py{version}".format(version=_version_nodot(py_version[:2]))
-    yield "py{major}".format(major=py_version[0])
+        yield f"py{_version_nodot(py_version[:2])}"
+    yield f"py{py_version[0]}"
     if len(py_version) > 1:
         for minor in range(py_version[1] - 1, -1, -1):
-            yield "py{version}".format(version=_version_nodot((py_version[0], minor)))
+            yield f"py{_version_nodot((py_version[0], minor))}"
 
 
 def compatible_tags(
@@ -290,7 +328,7 @@ def compatible_tags(
     """
     if not python_version:
         python_version = sys.version_info[:2]
-    platforms = list(platforms or _platform_tags())
+    platforms = list(platforms or platform_tags())
     for version in _py_interpreter_range(python_version):
         for platform_ in platforms:
             yield Tag(version, "none", platform_)
@@ -356,6 +394,22 @@ def mac_platforms(
     version_str, _, cpu_arch = platform.mac_ver()
     if version is None:
         version = cast("MacVersion", tuple(map(int, version_str.split(".")[:2])))
+        if version == (10, 16):
+            # When built against an older macOS SDK, Python will report macOS 10.16
+            # instead of the real version.
+            version_str = subprocess.run(
+                [
+                    sys.executable,
+                    "-sS",
+                    "-c",
+                    "import platform; print(platform.mac_ver()[0])",
+                ],
+                check=True,
+                env={"SYSTEM_VERSION_COMPAT": "0"},
+                stdout=subprocess.PIPE,
+                text=True,
+            ).stdout
+            version = cast("MacVersion", tuple(map(int, version_str.split(".")[:2])))
     else:
         version = version
     if arch is None:
@@ -416,22 +470,28 @@ def mac_platforms(
 
 def _linux_platforms(is_32bit: bool = _32_BIT_INTERPRETER) -> Iterator[str]:
     linux = _normalize_string(sysconfig.get_platform())
+    if not linux.startswith("linux_"):
+        # we should never be here, just yield the sysconfig one and return
+        yield linux
+        return
     if is_32bit:
         if linux == "linux_x86_64":
             linux = "linux_i686"
         elif linux == "linux_aarch64":
-            linux = "linux_armv7l"
+            linux = "linux_armv8l"
     _, arch = linux.split("_", 1)
-    yield from _manylinux.platform_tags(linux, arch)
-    yield from _musllinux.platform_tags(arch)
-    yield linux
+    archs = {"armv8l": ["armv8l", "armv7l"]}.get(arch, [arch])
+    yield from _manylinux.platform_tags(archs)
+    yield from _musllinux.platform_tags(archs)
+    for arch in archs:
+        yield f"linux_{arch}"
 
 
 def _generic_platforms() -> Iterator[str]:
     yield _normalize_string(sysconfig.get_platform())
 
 
-def _platform_tags() -> Iterator[str]:
+def platform_tags() -> Iterator[str]:
     """
     Provides the platform tags for this installation.
     """
@@ -446,6 +506,9 @@ def _platform_tags() -> Iterator[str]:
 def interpreter_name() -> str:
     """
     Returns the name of the running interpreter.
+
+    Some implementations have a reserved, two-letter abbreviation which will
+    be returned when appropriate.
     """
     name = sys.implementation.name
     return INTERPRETER_SHORT_NAMES.get(name) or name
@@ -481,4 +544,10 @@ def sys_tags(*, warn: bool = False) -> Iterator[Tag]:
     else:
         yield from generic_tags()
 
-    yield from compatible_tags()
+    if interp_name == "pp":
+        interp = "pp3"
+    elif interp_name == "cp":
+        interp = "cp" + interpreter_version(warn=warn)
+    else:
+        interp = None
+    yield from compatible_tags(interpreter=interp)
diff --git a/pip_api/_vendor/packaging/utils.py b/pip_api/_vendor/packaging/utils.py
index bab11b8..c2c2f75 100644
--- a/pip_api/_vendor/packaging/utils.py
+++ b/pip_api/_vendor/packaging/utils.py
@@ -12,6 +12,12 @@
 NormalizedName = NewType("NormalizedName", str)
 
 
+class InvalidName(ValueError):
+    """
+    An invalid distribution name; users should refer to the packaging user guide.
+    """
+
+
 class InvalidWheelFilename(ValueError):
     """
     An invalid wheel filename was found, users should refer to PEP 427.
@@ -24,18 +30,31 @@ class InvalidSdistFilename(ValueError):
     """
 
 
+# Core metadata spec for `Name`
+_validate_regex = re.compile(
+    r"^([A-Z0-9]|[A-Z0-9][A-Z0-9._-]*[A-Z0-9])$", re.IGNORECASE
+)
 _canonicalize_regex = re.compile(r"[-_.]+")
+_normalized_regex = re.compile(r"^([a-z0-9]|[a-z0-9]([a-z0-9-](?!--))*[a-z0-9])$")
 # PEP 427: The build number must start with a digit.
 _build_tag_regex = re.compile(r"(\d+)(.*)")
 
 
-def canonicalize_name(name: str) -> NormalizedName:
+def canonicalize_name(name: str, *, validate: bool = False) -> NormalizedName:
+    if validate and not _validate_regex.match(name):
+        raise InvalidName(f"name is invalid: {name!r}")
     # This is taken from PEP 503.
     value = _canonicalize_regex.sub("-", name).lower()
     return cast(NormalizedName, value)
 
 
-def canonicalize_version(version: Union[Version, str]) -> str:
+def is_normalized_name(name: str) -> bool:
+    return _normalized_regex.match(name) is not None
+
+
+def canonicalize_version(
+    version: Union[Version, str], *, strip_trailing_zero: bool = True
+) -> str:
     """
     This is very similar to Version.__str__, but has one subtle difference
     with the way it handles the release segment.
@@ -56,8 +75,11 @@ def canonicalize_version(version: Union[Version, str]) -> str:
         parts.append(f"{parsed.epoch}!")
 
     # Release segment
-    # NB: This strips trailing '.0's to normalize
-    parts.append(re.sub(r"(\.0)+$", "", ".".join(str(x) for x in parsed.release)))
+    release_segment = ".".join(str(x) for x in parsed.release)
+    if strip_trailing_zero:
+        # NB: This strips trailing '.0's to normalize
+        release_segment = re.sub(r"(\.0)+$", "", release_segment)
+    parts.append(release_segment)
 
     # Pre-release
     if parsed.pre is not None:
@@ -95,11 +117,18 @@ def parse_wheel_filename(
 
     parts = filename.split("-", dashes - 2)
     name_part = parts[0]
-    # See PEP 427 for the rules on escaping the project name
+    # See PEP 427 for the rules on escaping the project name.
     if "__" in name_part or re.match(r"^[\w\d._]*$", name_part, re.UNICODE) is None:
         raise InvalidWheelFilename(f"Invalid project name: {filename}")
     name = canonicalize_name(name_part)
-    version = Version(parts[1])
+
+    try:
+        version = Version(parts[1])
+    except InvalidVersion as e:
+        raise InvalidWheelFilename(
+            f"Invalid wheel filename (invalid version): {filename}"
+        ) from e
+
     if dashes == 5:
         build_part = parts[2]
         build_match = _build_tag_regex.match(build_part)
@@ -132,5 +161,12 @@ def parse_sdist_filename(filename: str) -> Tuple[NormalizedName, Version]:
         raise InvalidSdistFilename(f"Invalid sdist filename: {filename}")
 
     name = canonicalize_name(name_part)
-    version = Version(version_part)
+
+    try:
+        version = Version(version_part)
+    except InvalidVersion as e:
+        raise InvalidSdistFilename(
+            f"Invalid sdist filename (invalid version): {filename}"
+        ) from e
+
     return (name, version)
diff --git a/pip_api/_vendor/packaging/version.py b/pip_api/_vendor/packaging/version.py
index de9a09a..91b7bee 100644
--- a/pip_api/_vendor/packaging/version.py
+++ b/pip_api/_vendor/packaging/version.py
@@ -1,64 +1,71 @@
 # This file is dual licensed under the terms of the Apache License, Version
 # 2.0, and the BSD License. See the LICENSE file in the root of this repository
 # for complete details.
+"""
+.. testsetup::
+
+    from pip_api._vendor.packaging.version import parse, Version
+"""
 
-import collections
 import itertools
 import re
-import warnings
-from typing import Callable, Iterator, List, Optional, SupportsInt, Tuple, Union
+from typing import Any, Callable, NamedTuple, Optional, SupportsInt, Tuple, Union
 
 from ._structures import Infinity, InfinityType, NegativeInfinity, NegativeInfinityType
 
-__all__ = ["parse", "Version", "LegacyVersion", "InvalidVersion", "VERSION_PATTERN"]
+__all__ = ["VERSION_PATTERN", "parse", "Version", "InvalidVersion"]
 
-InfiniteTypes = Union[InfinityType, NegativeInfinityType]
-PrePostDevType = Union[InfiniteTypes, Tuple[str, int]]
-SubLocalType = Union[InfiniteTypes, int, str]
-LocalType = Union[
+LocalType = Tuple[Union[int, str], ...]
+
+CmpPrePostDevType = Union[InfinityType, NegativeInfinityType, Tuple[str, int]]
+CmpLocalType = Union[
     NegativeInfinityType,
-    Tuple[
-        Union[
-            SubLocalType,
-            Tuple[SubLocalType, str],
-            Tuple[NegativeInfinityType, SubLocalType],
-        ],
-        ...,
-    ],
+    Tuple[Union[Tuple[int, str], Tuple[NegativeInfinityType, Union[int, str]]], ...],
 ]
 CmpKey = Tuple[
-    int, Tuple[int, ...], PrePostDevType, PrePostDevType, PrePostDevType, LocalType
-]
-LegacyCmpKey = Tuple[int, Tuple[str, ...]]
-VersionComparisonMethod = Callable[
-    [Union[CmpKey, LegacyCmpKey], Union[CmpKey, LegacyCmpKey]], bool
+    int,
+    Tuple[int, ...],
+    CmpPrePostDevType,
+    CmpPrePostDevType,
+    CmpPrePostDevType,
+    CmpLocalType,
 ]
+VersionComparisonMethod = Callable[[CmpKey, CmpKey], bool]
 
-_Version = collections.namedtuple(
-    "_Version", ["epoch", "release", "dev", "pre", "post", "local"]
-)
 
+class _Version(NamedTuple):
+    epoch: int
+    release: Tuple[int, ...]
+    dev: Optional[Tuple[str, int]]
+    pre: Optional[Tuple[str, int]]
+    post: Optional[Tuple[str, int]]
+    local: Optional[LocalType]
 
-def parse(version: str) -> Union["LegacyVersion", "Version"]:
-    """
-    Parse the given version string and return either a :class:`Version` object
-    or a :class:`LegacyVersion` object depending on if the given version is
-    a valid PEP 440 version or a legacy version.
+
+def parse(version: str) -> "Version":
+    """Parse the given version string.
+
+    >>> parse('1.0.dev1')
+    <Version('1.0.dev1')>
+
+    :param version: The version string to parse.
+    :raises InvalidVersion: When the version string is not a valid version.
     """
-    try:
-        return Version(version)
-    except InvalidVersion:
-        return LegacyVersion(version)
+    return Version(version)
 
 
 class InvalidVersion(ValueError):
-    """
-    An invalid version was found, users should refer to PEP 440.
+    """Raised when a version string is not a valid version.
+
+    >>> Version("invalid")
+    Traceback (most recent call last):
+        ...
+    packaging.version.InvalidVersion: Invalid version: 'invalid'
     """
 
 
 class _BaseVersion:
-    _key: Union[CmpKey, LegacyCmpKey]
+    _key: Tuple[Any, ...]
 
     def __hash__(self) -> int:
         return hash(self._key)
@@ -103,133 +110,16 @@ def __ne__(self, other: object) -> bool:
         return self._key != other._key
 
 
-class LegacyVersion(_BaseVersion):
-    def __init__(self, version: str) -> None:
-        self._version = str(version)
-        self._key = _legacy_cmpkey(self._version)
-
-        warnings.warn(
-            "Creating a LegacyVersion has been deprecated and will be "
-            "removed in the next major release",
-            DeprecationWarning,
-        )
-
-    def __str__(self) -> str:
-        return self._version
-
-    def __repr__(self) -> str:
-        return f"<LegacyVersion('{self}')>"
-
-    @property
-    def public(self) -> str:
-        return self._version
-
-    @property
-    def base_version(self) -> str:
-        return self._version
-
-    @property
-    def epoch(self) -> int:
-        return -1
-
-    @property
-    def release(self) -> None:
-        return None
-
-    @property
-    def pre(self) -> None:
-        return None
-
-    @property
-    def post(self) -> None:
-        return None
-
-    @property
-    def dev(self) -> None:
-        return None
-
-    @property
-    def local(self) -> None:
-        return None
-
-    @property
-    def is_prerelease(self) -> bool:
-        return False
-
-    @property
-    def is_postrelease(self) -> bool:
-        return False
-
-    @property
-    def is_devrelease(self) -> bool:
-        return False
-
-
-_legacy_version_component_re = re.compile(r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE)
-
-_legacy_version_replacement_map = {
-    "pre": "c",
-    "preview": "c",
-    "-": "final-",
-    "rc": "c",
-    "dev": "@",
-}
-
-
-def _parse_version_parts(s: str) -> Iterator[str]:
-    for part in _legacy_version_component_re.split(s):
-        part = _legacy_version_replacement_map.get(part, part)
-
-        if not part or part == ".":
-            continue
-
-        if part[:1] in "0123456789":
-            # pad for numeric comparison
-            yield part.zfill(8)
-        else:
-            yield "*" + part
-
-    # ensure that alpha/beta/candidate are before final
-    yield "*final"
-
-
-def _legacy_cmpkey(version: str) -> LegacyCmpKey:
-
-    # We hardcode an epoch of -1 here. A PEP 440 version can only have a epoch
-    # greater than or equal to 0. This will effectively put the LegacyVersion,
-    # which uses the defacto standard originally implemented by setuptools,
-    # as before all PEP 440 versions.
-    epoch = -1
-
-    # This scheme is taken from pkg_resources.parse_version setuptools prior to
-    # it's adoption of the packaging library.
-    parts: List[str] = []
-    for part in _parse_version_parts(version.lower()):
-        if part.startswith("*"):
-            # remove "-" before a prerelease tag
-            if part < "*final":
-                while parts and parts[-1] == "*final-":
-                    parts.pop()
-
-            # remove trailing zeros from each series of numeric parts
-            while parts and parts[-1] == "00000000":
-                parts.pop()
-
-        parts.append(part)
-
-    return epoch, tuple(parts)
-
-
 # Deliberately not anchored to the start and end of the string, to make it
 # easier for 3rd party code to reuse
-VERSION_PATTERN = r"""
+_VERSION_PATTERN = r"""
     v?
     (?:
         (?:(?P<epoch>[0-9]+)!)?                           # epoch
         (?P<release>[0-9]+(?:\.[0-9]+)*)                  # release segment
         (?P<pre>                                          # pre-release
             [-_\.]?
-            (?P<pre_l>(a|b|c|rc|alpha|beta|pre|preview))
+            (?P<pre_l>alpha|a|beta|b|preview|pre|c|rc)
             [-_\.]?
             (?P<pre_n>[0-9]+)?
         )?
@@ -253,12 +143,56 @@ def _legacy_cmpkey(version: str) -> LegacyCmpKey:
     (?:\+(?P<local>[a-z0-9]+(?:[-_\.][a-z0-9]+)*))?       # local version
 """
 
+VERSION_PATTERN = _VERSION_PATTERN
+"""
+A string containing the regular expression used to match a valid version.
+
+The pattern is not anchored at either end, and is intended for embedding in larger
+expressions (for example, matching a version number as part of a file name). The
+regular expression should be compiled with the ``re.VERBOSE`` and ``re.IGNORECASE``
+flags set.
+
+:meta hide-value:
+"""
+
 
 class Version(_BaseVersion):
+    """This class abstracts handling of a project's versions.
+
+    A :class:`Version` instance is comparison aware and can be compared and
+    sorted using the standard Python interfaces.
+
+    >>> v1 = Version("1.0a5")
+    >>> v2 = Version("1.0")
+    >>> v1
+    <Version('1.0a5')>
+    >>> v2
+    <Version('1.0')>
+    >>> v1 < v2
+    True
+    >>> v1 == v2
+    False
+    >>> v1 > v2
+    False
+    >>> v1 >= v2
+    False
+    >>> v1 <= v2
+    True
+    """
 
     _regex = re.compile(r"^\s*" + VERSION_PATTERN + r"\s*$", re.VERBOSE | re.IGNORECASE)
+    _key: CmpKey
 
     def __init__(self, version: str) -> None:
+        """Initialize a Version object.
+
+        :param version:
+            The string representation of a version which will be parsed and normalized
+            before use.
+        :raises InvalidVersion:
+            If the ``version`` does not conform to PEP 440 in any way then this
+            exception will be raised.
+        """
 
         # Validate the version and parse it into pieces
         match = self._regex.search(version)
@@ -288,9 +222,19 @@ def __init__(self, version: str) -> None:
         )
 
     def __repr__(self) -> str:
+        """A representation of the Version that shows all internal state.
+
+        >>> Version('1.0.0')
+        <Version('1.0.0')>
+        """
         return f"<Version('{self}')>"
 
     def __str__(self) -> str:
+        """A string representation of the version that can be rounded-tripped.
+
+        >>> str(Version("1.0a5"))
+        '1.0a5'
+        """
         parts = []
 
         # Epoch
@@ -320,29 +264,77 @@ def __str__(self) -> str:
 
     @property
     def epoch(self) -> int:
-        _epoch: int = self._version.epoch
-        return _epoch
+        """The epoch of the version.
+
+        >>> Version("2.0.0").epoch
+        0
+        >>> Version("1!2.0.0").epoch
+        1
+        """
+        return self._version.epoch
 
     @property
     def release(self) -> Tuple[int, ...]:
-        _release: Tuple[int, ...] = self._version.release
-        return _release
+        """The components of the "release" segment of the version.
+
+        >>> Version("1.2.3").release
+        (1, 2, 3)
+        >>> Version("2.0.0").release
+        (2, 0, 0)
+        >>> Version("1!2.0.0.post0").release
+        (2, 0, 0)
+
+        Includes trailing zeroes but not the epoch or any pre-release / development /
+        post-release suffixes.
+        """
+        return self._version.release
 
     @property
     def pre(self) -> Optional[Tuple[str, int]]:
-        _pre: Optional[Tuple[str, int]] = self._version.pre
-        return _pre
+        """The pre-release segment of the version.
+
+        >>> print(Version("1.2.3").pre)
+        None
+        >>> Version("1.2.3a1").pre
+        ('a', 1)
+        >>> Version("1.2.3b1").pre
+        ('b', 1)
+        >>> Version("1.2.3rc1").pre
+        ('rc', 1)
+        """
+        return self._version.pre
 
     @property
     def post(self) -> Optional[int]:
+        """The post-release number of the version.
+
+        >>> print(Version("1.2.3").post)
+        None
+        >>> Version("1.2.3.post1").post
+        1
+        """
         return self._version.post[1] if self._version.post else None
 
     @property
     def dev(self) -> Optional[int]:
+        """The development number of the version.
+
+        >>> print(Version("1.2.3").dev)
+        None
+        >>> Version("1.2.3.dev1").dev
+        1
+        """
         return self._version.dev[1] if self._version.dev else None
 
     @property
     def local(self) -> Optional[str]:
+        """The local version segment of the version.
+
+        >>> print(Version("1.2.3").local)
+        None
+        >>> Version("1.2.3+abc").local
+        'abc'
+        """
         if self._version.local:
             return ".".join(str(x) for x in self._version.local)
         else:
@@ -350,10 +342,31 @@ def local(self) -> Optional[str]:
 
     @property
     def public(self) -> str:
+        """The public portion of the version.
+
+        >>> Version("1.2.3").public
+        '1.2.3'
+        >>> Version("1.2.3+abc").public
+        '1.2.3'
+        >>> Version("1.2.3+abc.dev1").public
+        '1.2.3'
+        """
         return str(self).split("+", 1)[0]
 
     @property
     def base_version(self) -> str:
+        """The "base version" of the version.
+
+        >>> Version("1.2.3").base_version
+        '1.2.3'
+        >>> Version("1.2.3+abc").base_version
+        '1.2.3'
+        >>> Version("1!1.2.3+abc.dev1").base_version
+        '1!1.2.3'
+
+        The "base version" is the public version of the project without any pre or post
+        release markers.
+        """
         parts = []
 
         # Epoch
@@ -367,31 +380,77 @@ def base_version(self) -> str:
 
     @property
     def is_prerelease(self) -> bool:
+        """Whether this version is a pre-release.
+
+        >>> Version("1.2.3").is_prerelease
+        False
+        >>> Version("1.2.3a1").is_prerelease
+        True
+        >>> Version("1.2.3b1").is_prerelease
+        True
+        >>> Version("1.2.3rc1").is_prerelease
+        True
+        >>> Version("1.2.3dev1").is_prerelease
+        True
+        """
         return self.dev is not None or self.pre is not None
 
     @property
     def is_postrelease(self) -> bool:
+        """Whether this version is a post-release.
+
+        >>> Version("1.2.3").is_postrelease
+        False
+        >>> Version("1.2.3.post1").is_postrelease
+        True
+        """
         return self.post is not None
 
     @property
     def is_devrelease(self) -> bool:
+        """Whether this version is a development release.
+
+        >>> Version("1.2.3").is_devrelease
+        False
+        >>> Version("1.2.3.dev1").is_devrelease
+        True
+        """
         return self.dev is not None
 
     @property
     def major(self) -> int:
+        """The first item of :attr:`release` or ``0`` if unavailable.
+
+        >>> Version("1.2.3").major
+        1
+        """
         return self.release[0] if len(self.release) >= 1 else 0
 
     @property
     def minor(self) -> int:
+        """The second item of :attr:`release` or ``0`` if unavailable.
+
+        >>> Version("1.2.3").minor
+        2
+        >>> Version("1").minor
+        0
+        """
         return self.release[1] if len(self.release) >= 2 else 0
 
     @property
     def micro(self) -> int:
+        """The third item of :attr:`release` or ``0`` if unavailable.
+
+        >>> Version("1.2.3").micro
+        3
+        >>> Version("1").micro
+        0
+        """
         return self.release[2] if len(self.release) >= 3 else 0
 
 
 def _parse_letter_version(
-    letter: str, number: Union[str, bytes, SupportsInt]
+    letter: Optional[str], number: Union[str, bytes, SupportsInt, None]
 ) -> Optional[Tuple[str, int]]:
 
     if letter:
@@ -429,7 +488,7 @@ def _parse_letter_version(
 _local_version_separators = re.compile(r"[\._-]")
 
 
-def _parse_local_version(local: str) -> Optional[LocalType]:
+def _parse_local_version(local: Optional[str]) -> Optional[LocalType]:
     """
     Takes a string like abc.1.twelve and turns it into ("abc", 1, "twelve").
     """
@@ -447,7 +506,7 @@ def _cmpkey(
     pre: Optional[Tuple[str, int]],
     post: Optional[Tuple[str, int]],
     dev: Optional[Tuple[str, int]],
-    local: Optional[Tuple[SubLocalType]],
+    local: Optional[LocalType],
 ) -> CmpKey:
 
     # When we compare a release version, we want to compare it with all of the
@@ -464,7 +523,7 @@ def _cmpkey(
     # if there is not a pre or a post segment. If we have one of those then
     # the normal sorting rules will handle this case correctly.
     if pre is None and post is None and dev is not None:
-        _pre: PrePostDevType = NegativeInfinity
+        _pre: CmpPrePostDevType = NegativeInfinity
     # Versions without a pre-release (except as noted above) should sort after
     # those with one.
     elif pre is None:
@@ -474,21 +533,21 @@ def _cmpkey(
 
     # Versions without a post segment should sort before those with one.
     if post is None:
-        _post: PrePostDevType = NegativeInfinity
+        _post: CmpPrePostDevType = NegativeInfinity
 
     else:
         _post = post
 
     # Versions without a development segment should sort after those with one.
     if dev is None:
-        _dev: PrePostDevType = Infinity
+        _dev: CmpPrePostDevType = Infinity
 
     else:
         _dev = dev
 
     if local is None:
         # Versions without a local segment should sort before those with one.
-        _local: LocalType = NegativeInfinity
+        _local: CmpLocalType = NegativeInfinity
     else:
         # Versions with a local segment need that segment parsed to implement
         # the sorting rules in PEP440.
diff --git a/pip_api/_vendor/packaging_legacy/LICENSE b/pip_api/_vendor/packaging_legacy/LICENSE
new file mode 100644
index 0000000..6f62d44
--- /dev/null
+++ b/pip_api/_vendor/packaging_legacy/LICENSE
@@ -0,0 +1,3 @@
+This software is made available under the terms of *either* of the licenses
+found in LICENSE.APACHE or LICENSE.BSD. Contributions to this software is made
+under the terms of *both* these licenses.
diff --git a/pip_api/_vendor/packaging_legacy/LICENSE.APACHE b/pip_api/_vendor/packaging_legacy/LICENSE.APACHE
new file mode 100644
index 0000000..f433b1a
--- /dev/null
+++ b/pip_api/_vendor/packaging_legacy/LICENSE.APACHE
@@ -0,0 +1,177 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
diff --git a/pip_api/_vendor/packaging_legacy/LICENSE.BSD b/pip_api/_vendor/packaging_legacy/LICENSE.BSD
new file mode 100644
index 0000000..42ce7b7
--- /dev/null
+++ b/pip_api/_vendor/packaging_legacy/LICENSE.BSD
@@ -0,0 +1,23 @@
+Copyright (c) Donald Stufft and individual contributors.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/pip_api/_vendor/packaging_legacy/__init__.py b/pip_api/_vendor/packaging_legacy/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pip_api/_vendor/packaging_legacy/version.py b/pip_api/_vendor/packaging_legacy/version.py
new file mode 100644
index 0000000..e387e79
--- /dev/null
+++ b/pip_api/_vendor/packaging_legacy/version.py
@@ -0,0 +1,135 @@
+import re
+from typing import Iterator, List, Tuple
+
+from pip_api._vendor.packaging.version import InvalidVersion, _BaseVersion, parse as _parse
+
+LegacyCmpKey = Tuple[int, Tuple[str, ...]]
+
+
+def parse(version: str) -> "_BaseVersion":
+    """
+    Parse the given version string and return either a :class:`Version` object
+    or a :class:`LegacyVersion` object depending on if the given version is
+    a valid PEP 440 version or a legacy version.
+    Parse the given version string.
+    Returns a :class:`Version` object, if the given version is a valid PEP 440 version.
+    Raises :class:`InvalidVersion` otherwise.
+    """
+    try:
+        return _parse(version)
+    except InvalidVersion:
+        return LegacyVersion(version)
+
+
+class LegacyVersion(_BaseVersion):
+
+    _key: LegacyCmpKey
+
+    def __init__(self, version: str) -> None:
+        self._version = str(version)
+        self._key: LegacyCmpKey = _legacy_cmpkey(self._version)
+
+    def __str__(self) -> str:
+        return self._version
+
+    def __repr__(self) -> str:
+        return f"<LegacyVersion('{self}')>"
+
+    @property
+    def public(self) -> str:
+        return self._version
+
+    @property
+    def base_version(self) -> str:
+        return self._version
+
+    @property
+    def epoch(self) -> int:
+        return -1
+
+    @property
+    def release(self) -> None:
+        return None
+
+    @property
+    def pre(self) -> None:
+        return None
+
+    @property
+    def post(self) -> None:
+        return None
+
+    @property
+    def dev(self) -> None:
+        return None
+
+    @property
+    def local(self) -> None:
+        return None
+
+    @property
+    def is_prerelease(self) -> bool:
+        return False
+
+    @property
+    def is_postrelease(self) -> bool:
+        return False
+
+    @property
+    def is_devrelease(self) -> bool:
+        return False
+
+
+_legacy_version_component_re = re.compile(r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE)
+
+_legacy_version_replacement_map = {
+    "pre": "c",
+    "preview": "c",
+    "-": "final-",
+    "rc": "c",
+    "dev": "@",
+}
+
+
+def _parse_version_parts(s: str) -> Iterator[str]:
+    for part in _legacy_version_component_re.split(s):
+        part = _legacy_version_replacement_map.get(part, part)
+
+        if not part or part == ".":
+            continue
+
+        if part[:1] in "0123456789":
+            # pad for numeric comparison
+            yield part.zfill(8)
+        else:
+            yield "*" + part
+
+    # ensure that alpha/beta/candidate are before final
+    yield "*final"
+
+
+def _legacy_cmpkey(version: str) -> LegacyCmpKey:
+
+    # We hardcode an epoch of -1 here. A PEP 440 version can only have a epoch
+    # greater than or equal to 0. This will effectively put the LegacyVersion,
+    # which uses the defacto standard originally implemented by setuptools,
+    # as before all PEP 440 versions.
+    epoch = -1
+
+    # This scheme is taken from pkg_resources.parse_version setuptools prior to
+    # it's adoption of the packaging library.
+    parts: List[str] = []
+    for part in _parse_version_parts(version.lower()):
+        if part.startswith("*"):
+            # remove "-" before a prerelease tag
+            if part < "*final":
+                while parts and parts[-1] == "*final-":
+                    parts.pop()
+
+            # remove trailing zeros from each series of numeric parts
+            while parts and parts[-1] == "00000000":
+                parts.pop()
+
+        parts.append(part)
+
+    return epoch, tuple(parts)
diff --git a/pip_api/_vendor/pyparsing.LICENSE b/pip_api/_vendor/pyparsing.LICENSE
deleted file mode 100644
index 1bf9852..0000000
--- a/pip_api/_vendor/pyparsing.LICENSE
+++ /dev/null
@@ -1,18 +0,0 @@
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/pip_api/_vendor/pyparsing.py b/pip_api/_vendor/pyparsing.py
deleted file mode 100644
index 71d3959..0000000
--- a/pip_api/_vendor/pyparsing.py
+++ /dev/null
@@ -1,7107 +0,0 @@
-# -*- coding: utf-8 -*-
-# module pyparsing.py
-#
-# Copyright (c) 2003-2019  Paul T. McGuire
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__doc__ = \
-"""
-pyparsing module - Classes and methods to define and execute parsing grammars
-=============================================================================
-
-The pyparsing module is an alternative approach to creating and
-executing simple grammars, vs. the traditional lex/yacc approach, or the
-use of regular expressions.  With pyparsing, you don't need to learn
-a new syntax for defining grammars or matching expressions - the parsing
-module provides a library of classes that you use to construct the
-grammar directly in Python.
-
-Here is a program to parse "Hello, World!" (or any greeting of the form
-``"<salutation>, <addressee>!"``), built up using :class:`Word`,
-:class:`Literal`, and :class:`And` elements
-(the :class:`'+'<ParserElement.__add__>` operators create :class:`And` expressions,
-and the strings are auto-converted to :class:`Literal` expressions)::
-
-    from pip_api._vendor.pyparsing import Word, alphas
-
-    # define grammar of a greeting
-    greet = Word(alphas) + "," + Word(alphas) + "!"
-
-    hello = "Hello, World!"
-    print (hello, "->", greet.parseString(hello))
-
-The program outputs the following::
-
-    Hello, World! -> ['Hello', ',', 'World', '!']
-
-The Python representation of the grammar is quite readable, owing to the
-self-explanatory class names, and the use of '+', '|' and '^' operators.
-
-The :class:`ParseResults` object returned from
-:class:`ParserElement.parseString` can be
-accessed as a nested list, a dictionary, or an object with named
-attributes.
-
-The pyparsing module handles some of the problems that are typically
-vexing when writing text parsers:
-
-  - extra or missing whitespace (the above program will also handle
-    "Hello,World!", "Hello  ,  World  !", etc.)
-  - quoted strings
-  - embedded comments
-
-
-Getting Started -
------------------
-Visit the classes :class:`ParserElement` and :class:`ParseResults` to
-see the base classes that most other pyparsing
-classes inherit from. Use the docstrings for examples of how to:
-
- - construct literal match expressions from :class:`Literal` and
-   :class:`CaselessLiteral` classes
- - construct character word-group expressions using the :class:`Word`
-   class
- - see how to create repetitive expressions using :class:`ZeroOrMore`
-   and :class:`OneOrMore` classes
- - use :class:`'+'<And>`, :class:`'|'<MatchFirst>`, :class:`'^'<Or>`,
-   and :class:`'&'<Each>` operators to combine simple expressions into
-   more complex ones
- - associate names with your parsed results using
-   :class:`ParserElement.setResultsName`
- - access the parsed data, which is returned as a :class:`ParseResults`
-   object
- - find some helpful expression short-cuts like :class:`delimitedList`
-   and :class:`oneOf`
- - find more useful common expressions in the :class:`pyparsing_common`
-   namespace class
-"""
-
-__version__ = "2.4.7"
-__versionTime__ = "30 Mar 2020 00:43 UTC"
-__author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"
-
-import string
-from weakref import ref as wkref
-import copy
-import sys
-import warnings
-import re
-import sre_constants
-import collections
-import pprint
-import traceback
-import types
-from datetime import datetime
-from operator import itemgetter
-import itertools
-from functools import wraps
-from contextlib import contextmanager
-
-try:
-    # Python 3
-    from itertools import filterfalse
-except ImportError:
-    from itertools import ifilterfalse as filterfalse
-
-try:
-    from _thread import RLock
-except ImportError:
-    from threading import RLock
-
-try:
-    # Python 3
-    from collections.abc import Iterable
-    from collections.abc import MutableMapping, Mapping
-except ImportError:
-    # Python 2.7
-    from collections import Iterable
-    from collections import MutableMapping, Mapping
-
-try:
-    from collections import OrderedDict as _OrderedDict
-except ImportError:
-    try:
-        from ordereddict import OrderedDict as _OrderedDict
-    except ImportError:
-        _OrderedDict = None
-
-try:
-    from types import SimpleNamespace
-except ImportError:
-    class SimpleNamespace: pass
-
-# version compatibility configuration
-__compat__ = SimpleNamespace()
-__compat__.__doc__ = """
-    A cross-version compatibility configuration for pyparsing features that will be
-    released in a future version. By setting values in this configuration to True,
-    those features can be enabled in prior versions for compatibility development
-    and testing.
-
-     - collect_all_And_tokens - flag to enable fix for Issue #63 that fixes erroneous grouping
-       of results names when an And expression is nested within an Or or MatchFirst; set to
-       True to enable bugfix released in pyparsing 2.3.0, or False to preserve
-       pre-2.3.0 handling of named results
-"""
-__compat__.collect_all_And_tokens = True
-
-__diag__ = SimpleNamespace()
-__diag__.__doc__ = """
-Diagnostic configuration (all default to False)
-     - warn_multiple_tokens_in_named_alternation - flag to enable warnings when a results
-       name is defined on a MatchFirst or Or expression with one or more And subexpressions
-       (only warns if __compat__.collect_all_And_tokens is False)
-     - warn_ungrouped_named_tokens_in_collection - flag to enable warnings when a results
-       name is defined on a containing expression with ungrouped subexpressions that also
-       have results names
-     - warn_name_set_on_empty_Forward - flag to enable warnings whan a Forward is defined
-       with a results name, but has no contents defined
-     - warn_on_multiple_string_args_to_oneof - flag to enable warnings whan oneOf is
-       incorrectly called with multiple str arguments
-     - enable_debug_on_named_expressions - flag to auto-enable debug on all subsequent
-       calls to ParserElement.setName()
-"""
-__diag__.warn_multiple_tokens_in_named_alternation = False
-__diag__.warn_ungrouped_named_tokens_in_collection = False
-__diag__.warn_name_set_on_empty_Forward = False
-__diag__.warn_on_multiple_string_args_to_oneof = False
-__diag__.enable_debug_on_named_expressions = False
-__diag__._all_names = [nm for nm in vars(__diag__) if nm.startswith("enable_") or nm.startswith("warn_")]
-
-def _enable_all_warnings():
-    __diag__.warn_multiple_tokens_in_named_alternation = True
-    __diag__.warn_ungrouped_named_tokens_in_collection = True
-    __diag__.warn_name_set_on_empty_Forward = True
-    __diag__.warn_on_multiple_string_args_to_oneof = True
-__diag__.enable_all_warnings = _enable_all_warnings
-
-
-__all__ = ['__version__', '__versionTime__', '__author__', '__compat__', '__diag__',
-           'And', 'CaselessKeyword', 'CaselessLiteral', 'CharsNotIn', 'Combine', 'Dict', 'Each', 'Empty',
-           'FollowedBy', 'Forward', 'GoToColumn', 'Group', 'Keyword', 'LineEnd', 'LineStart', 'Literal',
-           'PrecededBy', 'MatchFirst', 'NoMatch', 'NotAny', 'OneOrMore', 'OnlyOnce', 'Optional', 'Or',
-           'ParseBaseException', 'ParseElementEnhance', 'ParseException', 'ParseExpression', 'ParseFatalException',
-           'ParseResults', 'ParseSyntaxException', 'ParserElement', 'QuotedString', 'RecursiveGrammarException',
-           'Regex', 'SkipTo', 'StringEnd', 'StringStart', 'Suppress', 'Token', 'TokenConverter',
-           'White', 'Word', 'WordEnd', 'WordStart', 'ZeroOrMore', 'Char',
-           'alphanums', 'alphas', 'alphas8bit', 'anyCloseTag', 'anyOpenTag', 'cStyleComment', 'col',
-           'commaSeparatedList', 'commonHTMLEntity', 'countedArray', 'cppStyleComment', 'dblQuotedString',
-           'dblSlashComment', 'delimitedList', 'dictOf', 'downcaseTokens', 'empty', 'hexnums',
-           'htmlComment', 'javaStyleComment', 'line', 'lineEnd', 'lineStart', 'lineno',
-           'makeHTMLTags', 'makeXMLTags', 'matchOnlyAtCol', 'matchPreviousExpr', 'matchPreviousLiteral',
-           'nestedExpr', 'nullDebugAction', 'nums', 'oneOf', 'opAssoc', 'operatorPrecedence', 'printables',
-           'punc8bit', 'pythonStyleComment', 'quotedString', 'removeQuotes', 'replaceHTMLEntity',
-           'replaceWith', 'restOfLine', 'sglQuotedString', 'srange', 'stringEnd',
-           'stringStart', 'traceParseAction', 'unicodeString', 'upcaseTokens', 'withAttribute',
-           'indentedBlock', 'originalTextFor', 'ungroup', 'infixNotation', 'locatedExpr', 'withClass',
-           'CloseMatch', 'tokenMap', 'pyparsing_common', 'pyparsing_unicode', 'unicode_set',
-           'conditionAsParseAction', 're',
-           ]
-
-system_version = tuple(sys.version_info)[:3]
-PY_3 = system_version[0] == 3
-if PY_3:
-    _MAX_INT = sys.maxsize
-    basestring = str
-    unichr = chr
-    unicode = str
-    _ustr = str
-
-    # build list of single arg builtins, that can be used as parse actions
-    singleArgBuiltins = [sum, len, sorted, reversed, list, tuple, set, any, all, min, max]
-
-else:
-    _MAX_INT = sys.maxint
-    range = xrange
-
-    def _ustr(obj):
-        """Drop-in replacement for str(obj) that tries to be Unicode
-        friendly. It first tries str(obj). If that fails with
-        a UnicodeEncodeError, then it tries unicode(obj). It then
-        < returns the unicode object | encodes it with the default
-        encoding | ... >.
-        """
-        if isinstance(obj, unicode):
-            return obj
-
-        try:
-            # If this works, then _ustr(obj) has the same behaviour as str(obj), so
-            # it won't break any existing code.
-            return str(obj)
-
-        except UnicodeEncodeError:
-            # Else encode it
-            ret = unicode(obj).encode(sys.getdefaultencoding(), 'xmlcharrefreplace')
-            xmlcharref = Regex(r'&#\d+;')
-            xmlcharref.setParseAction(lambda t: '\\u' + hex(int(t[0][2:-1]))[2:])
-            return xmlcharref.transformString(ret)
-
-    # build list of single arg builtins, tolerant of Python version, that can be used as parse actions
-    singleArgBuiltins = []
-    import __builtin__
-
-    for fname in "sum len sorted reversed list tuple set any all min max".split():
-        try:
-            singleArgBuiltins.append(getattr(__builtin__, fname))
-        except AttributeError:
-            continue
-
-_generatorType = type((y for y in range(1)))
-
-def _xml_escape(data):
-    """Escape &, <, >, ", ', etc. in a string of data."""
-
-    # ampersand must be replaced first
-    from_symbols = '&><"\''
-    to_symbols = ('&' + s + ';' for s in "amp gt lt quot apos".split())
-    for from_, to_ in zip(from_symbols, to_symbols):
-        data = data.replace(from_, to_)
-    return data
-
-alphas = string.ascii_uppercase + string.ascii_lowercase
-nums = "0123456789"
-hexnums = nums + "ABCDEFabcdef"
-alphanums = alphas + nums
-_bslash = chr(92)
-printables = "".join(c for c in string.printable if c not in string.whitespace)
-
-
-def conditionAsParseAction(fn, message=None, fatal=False):
-    msg = message if message is not None else "failed user-defined condition"
-    exc_type = ParseFatalException if fatal else ParseException
-    fn = _trim_arity(fn)
-
-    @wraps(fn)
-    def pa(s, l, t):
-        if not bool(fn(s, l, t)):
-            raise exc_type(s, l, msg)
-
-    return pa
-
-class ParseBaseException(Exception):
-    """base exception class for all parsing runtime exceptions"""
-    # Performance tuning: we construct a *lot* of these, so keep this
-    # constructor as small and fast as possible
-    def __init__(self, pstr, loc=0, msg=None, elem=None):
-        self.loc = loc
-        if msg is None:
-            self.msg = pstr
-            self.pstr = ""
-        else:
-            self.msg = msg
-            self.pstr = pstr
-        self.parserElement = elem
-        self.args = (pstr, loc, msg)
-
-    @classmethod
-    def _from_exception(cls, pe):
-        """
-        internal factory method to simplify creating one type of ParseException
-        from another - avoids having __init__ signature conflicts among subclasses
-        """
-        return cls(pe.pstr, pe.loc, pe.msg, pe.parserElement)
-
-    def __getattr__(self, aname):
-        """supported attributes by name are:
-           - lineno - returns the line number of the exception text
-           - col - returns the column number of the exception text
-           - line - returns the line containing the exception text
-        """
-        if aname == "lineno":
-            return lineno(self.loc, self.pstr)
-        elif aname in ("col", "column"):
-            return col(self.loc, self.pstr)
-        elif aname == "line":
-            return line(self.loc, self.pstr)
-        else:
-            raise AttributeError(aname)
-
-    def __str__(self):
-        if self.pstr:
-            if self.loc >= len(self.pstr):
-                foundstr = ', found end of text'
-            else:
-                foundstr = (', found %r' % self.pstr[self.loc:self.loc + 1]).replace(r'\\', '\\')
-        else:
-            foundstr = ''
-        return ("%s%s  (at char %d), (line:%d, col:%d)" %
-                   (self.msg, foundstr, self.loc, self.lineno, self.column))
-    def __repr__(self):
-        return _ustr(self)
-    def markInputline(self, markerString=">!<"):
-        """Extracts the exception line from the input string, and marks
-           the location of the exception with a special symbol.
-        """
-        line_str = self.line
-        line_column = self.column - 1
-        if markerString:
-            line_str = "".join((line_str[:line_column],
-                                markerString, line_str[line_column:]))
-        return line_str.strip()
-    def __dir__(self):
-        return "lineno col line".split() + dir(type(self))
-
-class ParseException(ParseBaseException):
-    """
-    Exception thrown when parse expressions don't match class;
-    supported attributes by name are:
-    - lineno - returns the line number of the exception text
-    - col - returns the column number of the exception text
-    - line - returns the line containing the exception text
-
-    Example::
-
-        try:
-            Word(nums).setName("integer").parseString("ABC")
-        except ParseException as pe:
-            print(pe)
-            print("column: {}".format(pe.col))
-
-    prints::
-
-       Expected integer (at char 0), (line:1, col:1)
-        column: 1
-
-    """
-
-    @staticmethod
-    def explain(exc, depth=16):
-        """
-        Method to take an exception and translate the Python internal traceback into a list
-        of the pyparsing expressions that caused the exception to be raised.
-
-        Parameters:
-
-         - exc - exception raised during parsing (need not be a ParseException, in support
-           of Python exceptions that might be raised in a parse action)
-         - depth (default=16) - number of levels back in the stack trace to list expression
-           and function names; if None, the full stack trace names will be listed; if 0, only
-           the failing input line, marker, and exception string will be shown
-
-        Returns a multi-line string listing the ParserElements and/or function names in the
-        exception's stack trace.
-
-        Note: the diagnostic output will include string representations of the expressions
-        that failed to parse. These representations will be more helpful if you use `setName` to
-        give identifiable names to your expressions. Otherwise they will use the default string
-        forms, which may be cryptic to read.
-
-        explain() is only supported under Python 3.
-        """
-        import inspect
-
-        if depth is None:
-            depth = sys.getrecursionlimit()
-        ret = []
-        if isinstance(exc, ParseBaseException):
-            ret.append(exc.line)
-            ret.append(' ' * (exc.col - 1) + '^')
-        ret.append("{0}: {1}".format(type(exc).__name__, exc))
-
-        if depth > 0:
-            callers = inspect.getinnerframes(exc.__traceback__, context=depth)
-            seen = set()
-            for i, ff in enumerate(callers[-depth:]):
-                frm = ff[0]
-
-                f_self = frm.f_locals.get('self', None)
-                if isinstance(f_self, ParserElement):
-                    if frm.f_code.co_name not in ('parseImpl', '_parseNoCache'):
-                        continue
-                    if f_self in seen:
-                        continue
-                    seen.add(f_self)
-
-                    self_type = type(f_self)
-                    ret.append("{0}.{1} - {2}".format(self_type.__module__,
-                                                      self_type.__name__,
-                                                      f_self))
-                elif f_self is not None:
-                    self_type = type(f_self)
-                    ret.append("{0}.{1}".format(self_type.__module__,
-                                                self_type.__name__))
-                else:
-                    code = frm.f_code
-                    if code.co_name in ('wrapper', '<module>'):
-                        continue
-
-                    ret.append("{0}".format(code.co_name))
-
-                depth -= 1
-                if not depth:
-                    break
-
-        return '\n'.join(ret)
-
-
-class ParseFatalException(ParseBaseException):
-    """user-throwable exception thrown when inconsistent parse content
-       is found; stops all parsing immediately"""
-    pass
-
-class ParseSyntaxException(ParseFatalException):
-    """just like :class:`ParseFatalException`, but thrown internally
-    when an :class:`ErrorStop<And._ErrorStop>` ('-' operator) indicates
-    that parsing is to stop immediately because an unbacktrackable
-    syntax error has been found.
-    """
-    pass
-
-#~ class ReparseException(ParseBaseException):
-    #~ """Experimental class - parse actions can raise this exception to cause
-       #~ pyparsing to reparse the input string:
-        #~ - with a modified input string, and/or
-        #~ - with a modified start location
-       #~ Set the values of the ReparseException in the constructor, and raise the
-       #~ exception in a parse action to cause pyparsing to use the new string/location.
-       #~ Setting the values as None causes no change to be made.
-       #~ """
-    #~ def __init_( self, newstring, restartLoc ):
-        #~ self.newParseText = newstring
-        #~ self.reparseLoc = restartLoc
-
-class RecursiveGrammarException(Exception):
-    """exception thrown by :class:`ParserElement.validate` if the
-    grammar could be improperly recursive
-    """
-    def __init__(self, parseElementList):
-        self.parseElementTrace = parseElementList
-
-    def __str__(self):
-        return "RecursiveGrammarException: %s" % self.parseElementTrace
-
-class _ParseResultsWithOffset(object):
-    def __init__(self, p1, p2):
-        self.tup = (p1, p2)
-    def __getitem__(self, i):
-        return self.tup[i]
-    def __repr__(self):
-        return repr(self.tup[0])
-    def setOffset(self, i):
-        self.tup = (self.tup[0], i)
-
-class ParseResults(object):
-    """Structured parse results, to provide multiple means of access to
-    the parsed data:
-
-       - as a list (``len(results)``)
-       - by list index (``results[0], results[1]``, etc.)
-       - by attribute (``results.<resultsName>`` - see :class:`ParserElement.setResultsName`)
-
-    Example::
-
-        integer = Word(nums)
-        date_str = (integer.setResultsName("year") + '/'
-                        + integer.setResultsName("month") + '/'
-                        + integer.setResultsName("day"))
-        # equivalent form:
-        # date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-        # parseString returns a ParseResults object
-        result = date_str.parseString("1999/12/31")
-
-        def test(s, fn=repr):
-            print("%s -> %s" % (s, fn(eval(s))))
-        test("list(result)")
-        test("result[0]")
-        test("result['month']")
-        test("result.day")
-        test("'month' in result")
-        test("'minutes' in result")
-        test("result.dump()", str)
-
-    prints::
-
-        list(result) -> ['1999', '/', '12', '/', '31']
-        result[0] -> '1999'
-        result['month'] -> '12'
-        result.day -> '31'
-        'month' in result -> True
-        'minutes' in result -> False
-        result.dump() -> ['1999', '/', '12', '/', '31']
-        - day: 31
-        - month: 12
-        - year: 1999
-    """
-    def __new__(cls, toklist=None, name=None, asList=True, modal=True):
-        if isinstance(toklist, cls):
-            return toklist
-        retobj = object.__new__(cls)
-        retobj.__doinit = True
-        return retobj
-
-    # Performance tuning: we construct a *lot* of these, so keep this
-    # constructor as small and fast as possible
-    def __init__(self, toklist=None, name=None, asList=True, modal=True, isinstance=isinstance):
-        if self.__doinit:
-            self.__doinit = False
-            self.__name = None
-            self.__parent = None
-            self.__accumNames = {}
-            self.__asList = asList
-            self.__modal = modal
-            if toklist is None:
-                toklist = []
-            if isinstance(toklist, list):
-                self.__toklist = toklist[:]
-            elif isinstance(toklist, _generatorType):
-                self.__toklist = list(toklist)
-            else:
-                self.__toklist = [toklist]
-            self.__tokdict = dict()
-
-        if name is not None and name:
-            if not modal:
-                self.__accumNames[name] = 0
-            if isinstance(name, int):
-                name = _ustr(name)  # will always return a str, but use _ustr for consistency
-            self.__name = name
-            if not (isinstance(toklist, (type(None), basestring, list)) and toklist in (None, '', [])):
-                if isinstance(toklist, basestring):
-                    toklist = [toklist]
-                if asList:
-                    if isinstance(toklist, ParseResults):
-                        self[name] = _ParseResultsWithOffset(ParseResults(toklist.__toklist), 0)
-                    else:
-                        self[name] = _ParseResultsWithOffset(ParseResults(toklist[0]), 0)
-                    self[name].__name = name
-                else:
-                    try:
-                        self[name] = toklist[0]
-                    except (KeyError, TypeError, IndexError):
-                        self[name] = toklist
-
-    def __getitem__(self, i):
-        if isinstance(i, (int, slice)):
-            return self.__toklist[i]
-        else:
-            if i not in self.__accumNames:
-                return self.__tokdict[i][-1][0]
-            else:
-                return ParseResults([v[0] for v in self.__tokdict[i]])
-
-    def __setitem__(self, k, v, isinstance=isinstance):
-        if isinstance(v, _ParseResultsWithOffset):
-            self.__tokdict[k] = self.__tokdict.get(k, list()) + [v]
-            sub = v[0]
-        elif isinstance(k, (int, slice)):
-            self.__toklist[k] = v
-            sub = v
-        else:
-            self.__tokdict[k] = self.__tokdict.get(k, list()) + [_ParseResultsWithOffset(v, 0)]
-            sub = v
-        if isinstance(sub, ParseResults):
-            sub.__parent = wkref(self)
-
-    def __delitem__(self, i):
-        if isinstance(i, (int, slice)):
-            mylen = len(self.__toklist)
-            del self.__toklist[i]
-
-            # convert int to slice
-            if isinstance(i, int):
-                if i < 0:
-                    i += mylen
-                i = slice(i, i + 1)
-            # get removed indices
-            removed = list(range(*i.indices(mylen)))
-            removed.reverse()
-            # fixup indices in token dictionary
-            for name, occurrences in self.__tokdict.items():
-                for j in removed:
-                    for k, (value, position) in enumerate(occurrences):
-                        occurrences[k] = _ParseResultsWithOffset(value, position - (position > j))
-        else:
-            del self.__tokdict[i]
-
-    def __contains__(self, k):
-        return k in self.__tokdict
-
-    def __len__(self):
-        return len(self.__toklist)
-
-    def __bool__(self):
-        return (not not self.__toklist)
-    __nonzero__ = __bool__
-
-    def __iter__(self):
-        return iter(self.__toklist)
-
-    def __reversed__(self):
-        return iter(self.__toklist[::-1])
-
-    def _iterkeys(self):
-        if hasattr(self.__tokdict, "iterkeys"):
-            return self.__tokdict.iterkeys()
-        else:
-            return iter(self.__tokdict)
-
-    def _itervalues(self):
-        return (self[k] for k in self._iterkeys())
-
-    def _iteritems(self):
-        return ((k, self[k]) for k in self._iterkeys())
-
-    if PY_3:
-        keys = _iterkeys
-        """Returns an iterator of all named result keys."""
-
-        values = _itervalues
-        """Returns an iterator of all named result values."""
-
-        items = _iteritems
-        """Returns an iterator of all named result key-value tuples."""
-
-    else:
-        iterkeys = _iterkeys
-        """Returns an iterator of all named result keys (Python 2.x only)."""
-
-        itervalues = _itervalues
-        """Returns an iterator of all named result values (Python 2.x only)."""
-
-        iteritems = _iteritems
-        """Returns an iterator of all named result key-value tuples (Python 2.x only)."""
-
-        def keys(self):
-            """Returns all named result keys (as a list in Python 2.x, as an iterator in Python 3.x)."""
-            return list(self.iterkeys())
-
-        def values(self):
-            """Returns all named result values (as a list in Python 2.x, as an iterator in Python 3.x)."""
-            return list(self.itervalues())
-
-        def items(self):
-            """Returns all named result key-values (as a list of tuples in Python 2.x, as an iterator in Python 3.x)."""
-            return list(self.iteritems())
-
-    def haskeys(self):
-        """Since keys() returns an iterator, this method is helpful in bypassing
-           code that looks for the existence of any defined results names."""
-        return bool(self.__tokdict)
-
-    def pop(self, *args, **kwargs):
-        """
-        Removes and returns item at specified index (default= ``last``).
-        Supports both ``list`` and ``dict`` semantics for ``pop()``. If
-        passed no argument or an integer argument, it will use ``list``
-        semantics and pop tokens from the list of parsed tokens. If passed
-        a non-integer argument (most likely a string), it will use ``dict``
-        semantics and pop the corresponding value from any defined results
-        names. A second default return value argument is supported, just as in
-        ``dict.pop()``.
-
-        Example::
-
-            def remove_first(tokens):
-                tokens.pop(0)
-            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
-            print(OneOrMore(Word(nums)).addParseAction(remove_first).parseString("0 123 321")) # -> ['123', '321']
-
-            label = Word(alphas)
-            patt = label("LABEL") + OneOrMore(Word(nums))
-            print(patt.parseString("AAB 123 321").dump())
-
-            # Use pop() in a parse action to remove named result (note that corresponding value is not
-            # removed from list form of results)
-            def remove_LABEL(tokens):
-                tokens.pop("LABEL")
-                return tokens
-            patt.addParseAction(remove_LABEL)
-            print(patt.parseString("AAB 123 321").dump())
-
-        prints::
-
-            ['AAB', '123', '321']
-            - LABEL: AAB
-
-            ['AAB', '123', '321']
-        """
-        if not args:
-            args = [-1]
-        for k, v in kwargs.items():
-            if k == 'default':
-                args = (args[0], v)
-            else:
-                raise TypeError("pop() got an unexpected keyword argument '%s'" % k)
-        if (isinstance(args[0], int)
-                or len(args) == 1
-                or args[0] in self):
-            index = args[0]
-            ret = self[index]
-            del self[index]
-            return ret
-        else:
-            defaultvalue = args[1]
-            return defaultvalue
-
-    def get(self, key, defaultValue=None):
-        """
-        Returns named result matching the given key, or if there is no
-        such name, then returns the given ``defaultValue`` or ``None`` if no
-        ``defaultValue`` is specified.
-
-        Similar to ``dict.get()``.
-
-        Example::
-
-            integer = Word(nums)
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-            result = date_str.parseString("1999/12/31")
-            print(result.get("year")) # -> '1999'
-            print(result.get("hour", "not specified")) # -> 'not specified'
-            print(result.get("hour")) # -> None
-        """
-        if key in self:
-            return self[key]
-        else:
-            return defaultValue
-
-    def insert(self, index, insStr):
-        """
-        Inserts new element at location index in the list of parsed tokens.
-
-        Similar to ``list.insert()``.
-
-        Example::
-
-            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
-
-            # use a parse action to insert the parse location in the front of the parsed results
-            def insert_locn(locn, tokens):
-                tokens.insert(0, locn)
-            print(OneOrMore(Word(nums)).addParseAction(insert_locn).parseString("0 123 321")) # -> [0, '0', '123', '321']
-        """
-        self.__toklist.insert(index, insStr)
-        # fixup indices in token dictionary
-        for name, occurrences in self.__tokdict.items():
-            for k, (value, position) in enumerate(occurrences):
-                occurrences[k] = _ParseResultsWithOffset(value, position + (position > index))
-
-    def append(self, item):
-        """
-        Add single element to end of ParseResults list of elements.
-
-        Example::
-
-            print(OneOrMore(Word(nums)).parseString("0 123 321")) # -> ['0', '123', '321']
-
-            # use a parse action to compute the sum of the parsed integers, and add it to the end
-            def append_sum(tokens):
-                tokens.append(sum(map(int, tokens)))
-            print(OneOrMore(Word(nums)).addParseAction(append_sum).parseString("0 123 321")) # -> ['0', '123', '321', 444]
-        """
-        self.__toklist.append(item)
-
-    def extend(self, itemseq):
-        """
-        Add sequence of elements to end of ParseResults list of elements.
-
-        Example::
-
-            patt = OneOrMore(Word(alphas))
-
-            # use a parse action to append the reverse of the matched strings, to make a palindrome
-            def make_palindrome(tokens):
-                tokens.extend(reversed([t[::-1] for t in tokens]))
-                return ''.join(tokens)
-            print(patt.addParseAction(make_palindrome).parseString("lskdj sdlkjf lksd")) # -> 'lskdjsdlkjflksddsklfjkldsjdksl'
-        """
-        if isinstance(itemseq, ParseResults):
-            self.__iadd__(itemseq)
-        else:
-            self.__toklist.extend(itemseq)
-
-    def clear(self):
-        """
-        Clear all elements and results names.
-        """
-        del self.__toklist[:]
-        self.__tokdict.clear()
-
-    def __getattr__(self, name):
-        try:
-            return self[name]
-        except KeyError:
-            return ""
-
-    def __add__(self, other):
-        ret = self.copy()
-        ret += other
-        return ret
-
-    def __iadd__(self, other):
-        if other.__tokdict:
-            offset = len(self.__toklist)
-            addoffset = lambda a: offset if a < 0 else a + offset
-            otheritems = other.__tokdict.items()
-            otherdictitems = [(k, _ParseResultsWithOffset(v[0], addoffset(v[1])))
-                              for k, vlist in otheritems for v in vlist]
-            for k, v in otherdictitems:
-                self[k] = v
-                if isinstance(v[0], ParseResults):
-                    v[0].__parent = wkref(self)
-
-        self.__toklist += other.__toklist
-        self.__accumNames.update(other.__accumNames)
-        return self
-
-    def __radd__(self, other):
-        if isinstance(other, int) and other == 0:
-            # useful for merging many ParseResults using sum() builtin
-            return self.copy()
-        else:
-            # this may raise a TypeError - so be it
-            return other + self
-
-    def __repr__(self):
-        return "(%s, %s)" % (repr(self.__toklist), repr(self.__tokdict))
-
-    def __str__(self):
-        return '[' + ', '.join(_ustr(i) if isinstance(i, ParseResults) else repr(i) for i in self.__toklist) + ']'
-
-    def _asStringList(self, sep=''):
-        out = []
-        for item in self.__toklist:
-            if out and sep:
-                out.append(sep)
-            if isinstance(item, ParseResults):
-                out += item._asStringList()
-            else:
-                out.append(_ustr(item))
-        return out
-
-    def asList(self):
-        """
-        Returns the parse results as a nested list of matching tokens, all converted to strings.
-
-        Example::
-
-            patt = OneOrMore(Word(alphas))
-            result = patt.parseString("sldkj lsdkj sldkj")
-            # even though the result prints in string-like form, it is actually a pyparsing ParseResults
-            print(type(result), result) # -> <class 'pyparsing.ParseResults'> ['sldkj', 'lsdkj', 'sldkj']
-
-            # Use asList() to create an actual list
-            result_list = result.asList()
-            print(type(result_list), result_list) # -> <class 'list'> ['sldkj', 'lsdkj', 'sldkj']
-        """
-        return [res.asList() if isinstance(res, ParseResults) else res for res in self.__toklist]
-
-    def asDict(self):
-        """
-        Returns the named parse results as a nested dictionary.
-
-        Example::
-
-            integer = Word(nums)
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-            result = date_str.parseString('12/31/1999')
-            print(type(result), repr(result)) # -> <class 'pyparsing.ParseResults'> (['12', '/', '31', '/', '1999'], {'day': [('1999', 4)], 'year': [('12', 0)], 'month': [('31', 2)]})
-
-            result_dict = result.asDict()
-            print(type(result_dict), repr(result_dict)) # -> <class 'dict'> {'day': '1999', 'year': '12', 'month': '31'}
-
-            # even though a ParseResults supports dict-like access, sometime you just need to have a dict
-            import json
-            print(json.dumps(result)) # -> Exception: TypeError: ... is not JSON serializable
-            print(json.dumps(result.asDict())) # -> {"month": "31", "day": "1999", "year": "12"}
-        """
-        if PY_3:
-            item_fn = self.items
-        else:
-            item_fn = self.iteritems
-
-        def toItem(obj):
-            if isinstance(obj, ParseResults):
-                if obj.haskeys():
-                    return obj.asDict()
-                else:
-                    return [toItem(v) for v in obj]
-            else:
-                return obj
-
-        return dict((k, toItem(v)) for k, v in item_fn())
-
-    def copy(self):
-        """
-        Returns a new copy of a :class:`ParseResults` object.
-        """
-        ret = ParseResults(self.__toklist)
-        ret.__tokdict = dict(self.__tokdict.items())
-        ret.__parent = self.__parent
-        ret.__accumNames.update(self.__accumNames)
-        ret.__name = self.__name
-        return ret
-
-    def asXML(self, doctag=None, namedItemsOnly=False, indent="", formatted=True):
-        """
-        (Deprecated) Returns the parse results as XML. Tags are created for tokens and lists that have defined results names.
-        """
-        nl = "\n"
-        out = []
-        namedItems = dict((v[1], k) for (k, vlist) in self.__tokdict.items()
-                          for v in vlist)
-        nextLevelIndent = indent + "  "
-
-        # collapse out indents if formatting is not desired
-        if not formatted:
-            indent = ""
-            nextLevelIndent = ""
-            nl = ""
-
-        selfTag = None
-        if doctag is not None:
-            selfTag = doctag
-        else:
-            if self.__name:
-                selfTag = self.__name
-
-        if not selfTag:
-            if namedItemsOnly:
-                return ""
-            else:
-                selfTag = "ITEM"
-
-        out += [nl, indent, "<", selfTag, ">"]
-
-        for i, res in enumerate(self.__toklist):
-            if isinstance(res, ParseResults):
-                if i in namedItems:
-                    out += [res.asXML(namedItems[i],
-                                      namedItemsOnly and doctag is None,
-                                      nextLevelIndent,
-                                      formatted)]
-                else:
-                    out += [res.asXML(None,
-                                      namedItemsOnly and doctag is None,
-                                      nextLevelIndent,
-                                      formatted)]
-            else:
-                # individual token, see if there is a name for it
-                resTag = None
-                if i in namedItems:
-                    resTag = namedItems[i]
-                if not resTag:
-                    if namedItemsOnly:
-                        continue
-                    else:
-                        resTag = "ITEM"
-                xmlBodyText = _xml_escape(_ustr(res))
-                out += [nl, nextLevelIndent, "<", resTag, ">",
-                        xmlBodyText,
-                                                "</", resTag, ">"]
-
-        out += [nl, indent, "</", selfTag, ">"]
-        return "".join(out)
-
-    def __lookup(self, sub):
-        for k, vlist in self.__tokdict.items():
-            for v, loc in vlist:
-                if sub is v:
-                    return k
-        return None
-
-    def getName(self):
-        r"""
-        Returns the results name for this token expression. Useful when several
-        different expressions might match at a particular location.
-
-        Example::
-
-            integer = Word(nums)
-            ssn_expr = Regex(r"\d\d\d-\d\d-\d\d\d\d")
-            house_number_expr = Suppress('#') + Word(nums, alphanums)
-            user_data = (Group(house_number_expr)("house_number")
-                        | Group(ssn_expr)("ssn")
-                        | Group(integer)("age"))
-            user_info = OneOrMore(user_data)
-
-            result = user_info.parseString("22 111-22-3333 #221B")
-            for item in result:
-                print(item.getName(), ':', item[0])
-
-        prints::
-
-            age : 22
-            ssn : 111-22-3333
-            house_number : 221B
-        """
-        if self.__name:
-            return self.__name
-        elif self.__parent:
-            par = self.__parent()
-            if par:
-                return par.__lookup(self)
-            else:
-                return None
-        elif (len(self) == 1
-              and len(self.__tokdict) == 1
-              and next(iter(self.__tokdict.values()))[0][1] in (0, -1)):
-            return next(iter(self.__tokdict.keys()))
-        else:
-            return None
-
-    def dump(self, indent='', full=True, include_list=True, _depth=0):
-        """
-        Diagnostic method for listing out the contents of
-        a :class:`ParseResults`. Accepts an optional ``indent`` argument so
-        that this string can be embedded in a nested display of other data.
-
-        Example::
-
-            integer = Word(nums)
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-            result = date_str.parseString('12/31/1999')
-            print(result.dump())
-
-        prints::
-
-            ['12', '/', '31', '/', '1999']
-            - day: 1999
-            - month: 31
-            - year: 12
-        """
-        out = []
-        NL = '\n'
-        if include_list:
-            out.append(indent + _ustr(self.asList()))
-        else:
-            out.append('')
-
-        if full:
-            if self.haskeys():
-                items = sorted((str(k), v) for k, v in self.items())
-                for k, v in items:
-                    if out:
-                        out.append(NL)
-                    out.append("%s%s- %s: " % (indent, ('  ' * _depth), k))
-                    if isinstance(v, ParseResults):
-                        if v:
-                            out.append(v.dump(indent=indent, full=full, include_list=include_list, _depth=_depth + 1))
-                        else:
-                            out.append(_ustr(v))
-                    else:
-                        out.append(repr(v))
-            elif any(isinstance(vv, ParseResults) for vv in self):
-                v = self
-                for i, vv in enumerate(v):
-                    if isinstance(vv, ParseResults):
-                        out.append("\n%s%s[%d]:\n%s%s%s" % (indent,
-                                                            ('  ' * (_depth)),
-                                                            i,
-                                                            indent,
-                                                            ('  ' * (_depth + 1)),
-                                                            vv.dump(indent=indent,
-                                                                    full=full,
-                                                                    include_list=include_list,
-                                                                    _depth=_depth + 1)))
-                    else:
-                        out.append("\n%s%s[%d]:\n%s%s%s" % (indent,
-                                                            ('  ' * (_depth)),
-                                                            i,
-                                                            indent,
-                                                            ('  ' * (_depth + 1)),
-                                                            _ustr(vv)))
-
-        return "".join(out)
-
-    def pprint(self, *args, **kwargs):
-        """
-        Pretty-printer for parsed results as a list, using the
-        `pprint <https://docs.python.org/3/library/pprint.html>`_ module.
-        Accepts additional positional or keyword args as defined for
-        `pprint.pprint <https://docs.python.org/3/library/pprint.html#pprint.pprint>`_ .
-
-        Example::
-
-            ident = Word(alphas, alphanums)
-            num = Word(nums)
-            func = Forward()
-            term = ident | num | Group('(' + func + ')')
-            func <<= ident + Group(Optional(delimitedList(term)))
-            result = func.parseString("fna a,b,(fnb c,d,200),100")
-            result.pprint(width=40)
-
-        prints::
-
-            ['fna',
-             ['a',
-              'b',
-              ['(', 'fnb', ['c', 'd', '200'], ')'],
-              '100']]
-        """
-        pprint.pprint(self.asList(), *args, **kwargs)
-
-    # add support for pickle protocol
-    def __getstate__(self):
-        return (self.__toklist,
-                (self.__tokdict.copy(),
-                 self.__parent is not None and self.__parent() or None,
-                 self.__accumNames,
-                 self.__name))
-
-    def __setstate__(self, state):
-        self.__toklist = state[0]
-        self.__tokdict, par, inAccumNames, self.__name = state[1]
-        self.__accumNames = {}
-        self.__accumNames.update(inAccumNames)
-        if par is not None:
-            self.__parent = wkref(par)
-        else:
-            self.__parent = None
-
-    def __getnewargs__(self):
-        return self.__toklist, self.__name, self.__asList, self.__modal
-
-    def __dir__(self):
-        return dir(type(self)) + list(self.keys())
-
-    @classmethod
-    def from_dict(cls, other, name=None):
-        """
-        Helper classmethod to construct a ParseResults from a dict, preserving the
-        name-value relations as results names. If an optional 'name' argument is
-        given, a nested ParseResults will be returned
-        """
-        def is_iterable(obj):
-            try:
-                iter(obj)
-            except Exception:
-                return False
-            else:
-                if PY_3:
-                    return not isinstance(obj, (str, bytes))
-                else:
-                    return not isinstance(obj, basestring)
-
-        ret = cls([])
-        for k, v in other.items():
-            if isinstance(v, Mapping):
-                ret += cls.from_dict(v, name=k)
-            else:
-                ret += cls([v], name=k, asList=is_iterable(v))
-        if name is not None:
-            ret = cls([ret], name=name)
-        return ret
-
-MutableMapping.register(ParseResults)
-
-def col (loc, strg):
-    """Returns current column within a string, counting newlines as line separators.
-   The first column is number 1.
-
-   Note: the default parsing behavior is to expand tabs in the input string
-   before starting the parsing process.  See
-   :class:`ParserElement.parseString` for more
-   information on parsing strings containing ``<TAB>`` s, and suggested
-   methods to maintain a consistent view of the parsed string, the parse
-   location, and line and column positions within the parsed string.
-   """
-    s = strg
-    return 1 if 0 < loc < len(s) and s[loc-1] == '\n' else loc - s.rfind("\n", 0, loc)
-
-def lineno(loc, strg):
-    """Returns current line number within a string, counting newlines as line separators.
-    The first line is number 1.
-
-    Note - the default parsing behavior is to expand tabs in the input string
-    before starting the parsing process.  See :class:`ParserElement.parseString`
-    for more information on parsing strings containing ``<TAB>`` s, and
-    suggested methods to maintain a consistent view of the parsed string, the
-    parse location, and line and column positions within the parsed string.
-    """
-    return strg.count("\n", 0, loc) + 1
-
-def line(loc, strg):
-    """Returns the line of text containing loc within a string, counting newlines as line separators.
-       """
-    lastCR = strg.rfind("\n", 0, loc)
-    nextCR = strg.find("\n", loc)
-    if nextCR >= 0:
-        return strg[lastCR + 1:nextCR]
-    else:
-        return strg[lastCR + 1:]
-
-def _defaultStartDebugAction(instring, loc, expr):
-    print(("Match " + _ustr(expr) + " at loc " + _ustr(loc) + "(%d,%d)" % (lineno(loc, instring), col(loc, instring))))
-
-def _defaultSuccessDebugAction(instring, startloc, endloc, expr, toks):
-    print("Matched " + _ustr(expr) + " -> " + str(toks.asList()))
-
-def _defaultExceptionDebugAction(instring, loc, expr, exc):
-    print("Exception raised:" + _ustr(exc))
-
-def nullDebugAction(*args):
-    """'Do-nothing' debug action, to suppress debugging output during parsing."""
-    pass
-
-# Only works on Python 3.x - nonlocal is toxic to Python 2 installs
-#~ 'decorator to trim function calls to match the arity of the target'
-#~ def _trim_arity(func, maxargs=3):
-    #~ if func in singleArgBuiltins:
-        #~ return lambda s,l,t: func(t)
-    #~ limit = 0
-    #~ foundArity = False
-    #~ def wrapper(*args):
-        #~ nonlocal limit,foundArity
-        #~ while 1:
-            #~ try:
-                #~ ret = func(*args[limit:])
-                #~ foundArity = True
-                #~ return ret
-            #~ except TypeError:
-                #~ if limit == maxargs or foundArity:
-                    #~ raise
-                #~ limit += 1
-                #~ continue
-    #~ return wrapper
-
-# this version is Python 2.x-3.x cross-compatible
-'decorator to trim function calls to match the arity of the target'
-def _trim_arity(func, maxargs=2):
-    if func in singleArgBuiltins:
-        return lambda s, l, t: func(t)
-    limit = [0]
-    foundArity = [False]
-
-    # traceback return data structure changed in Py3.5 - normalize back to plain tuples
-    if system_version[:2] >= (3, 5):
-        def extract_stack(limit=0):
-            # special handling for Python 3.5.0 - extra deep call stack by 1
-            offset = -3 if system_version == (3, 5, 0) else -2
-            frame_summary = traceback.extract_stack(limit=-offset + limit - 1)[offset]
-            return [frame_summary[:2]]
-        def extract_tb(tb, limit=0):
-            frames = traceback.extract_tb(tb, limit=limit)
-            frame_summary = frames[-1]
-            return [frame_summary[:2]]
-    else:
-        extract_stack = traceback.extract_stack
-        extract_tb = traceback.extract_tb
-
-    # synthesize what would be returned by traceback.extract_stack at the call to
-    # user's parse action 'func', so that we don't incur call penalty at parse time
-
-    LINE_DIFF = 6
-    # IF ANY CODE CHANGES, EVEN JUST COMMENTS OR BLANK LINES, BETWEEN THE NEXT LINE AND
-    # THE CALL TO FUNC INSIDE WRAPPER, LINE_DIFF MUST BE MODIFIED!!!!
-    this_line = extract_stack(limit=2)[-1]
-    pa_call_line_synth = (this_line[0], this_line[1] + LINE_DIFF)
-
-    def wrapper(*args):
-        while 1:
-            try:
-                ret = func(*args[limit[0]:])
-                foundArity[0] = True
-                return ret
-            except TypeError:
-                # re-raise TypeErrors if they did not come from our arity testing
-                if foundArity[0]:
-                    raise
-                else:
-                    try:
-                        tb = sys.exc_info()[-1]
-                        if not extract_tb(tb, limit=2)[-1][:2] == pa_call_line_synth:
-                            raise
-                    finally:
-                        try:
-                            del tb
-                        except NameError:
-                            pass
-
-                if limit[0] <= maxargs:
-                    limit[0] += 1
-                    continue
-                raise
-
-    # copy func name to wrapper for sensible debug output
-    func_name = "<parse action>"
-    try:
-        func_name = getattr(func, '__name__',
-                            getattr(func, '__class__').__name__)
-    except Exception:
-        func_name = str(func)
-    wrapper.__name__ = func_name
-
-    return wrapper
-
-
-class ParserElement(object):
-    """Abstract base level parser element class."""
-    DEFAULT_WHITE_CHARS = " \n\t\r"
-    verbose_stacktrace = False
-
-    @staticmethod
-    def setDefaultWhitespaceChars(chars):
-        r"""
-        Overrides the default whitespace chars
-
-        Example::
-
-            # default whitespace chars are space, <TAB> and newline
-            OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def', 'ghi', 'jkl']
-
-            # change to just treat newline as significant
-            ParserElement.setDefaultWhitespaceChars(" \t")
-            OneOrMore(Word(alphas)).parseString("abc def\nghi jkl")  # -> ['abc', 'def']
-        """
-        ParserElement.DEFAULT_WHITE_CHARS = chars
-
-    @staticmethod
-    def inlineLiteralsUsing(cls):
-        """
-        Set class to be used for inclusion of string literals into a parser.
-
-        Example::
-
-            # default literal class used is Literal
-            integer = Word(nums)
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-            date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']
-
-
-            # change to Suppress
-            ParserElement.inlineLiteralsUsing(Suppress)
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-
-            date_str.parseString("1999/12/31")  # -> ['1999', '12', '31']
-        """
-        ParserElement._literalStringClass = cls
-
-    @classmethod
-    def _trim_traceback(cls, tb):
-        while tb.tb_next:
-            tb = tb.tb_next
-        return tb
-
-    def __init__(self, savelist=False):
-        self.parseAction = list()
-        self.failAction = None
-        # ~ self.name = "<unknown>"  # don't define self.name, let subclasses try/except upcall
-        self.strRepr = None
-        self.resultsName = None
-        self.saveAsList = savelist
-        self.skipWhitespace = True
-        self.whiteChars = set(ParserElement.DEFAULT_WHITE_CHARS)
-        self.copyDefaultWhiteChars = True
-        self.mayReturnEmpty = False # used when checking for left-recursion
-        self.keepTabs = False
-        self.ignoreExprs = list()
-        self.debug = False
-        self.streamlined = False
-        self.mayIndexError = True # used to optimize exception handling for subclasses that don't advance parse index
-        self.errmsg = ""
-        self.modalResults = True # used to mark results names as modal (report only last) or cumulative (list all)
-        self.debugActions = (None, None, None)  # custom debug actions
-        self.re = None
-        self.callPreparse = True # used to avoid redundant calls to preParse
-        self.callDuringTry = False
-
-    def copy(self):
-        """
-        Make a copy of this :class:`ParserElement`.  Useful for defining
-        different parse actions for the same parsing pattern, using copies of
-        the original parse element.
-
-        Example::
-
-            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
-            integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K")
-            integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")
-
-            print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M"))
-
-        prints::
-
-            [5120, 100, 655360, 268435456]
-
-        Equivalent form of ``expr.copy()`` is just ``expr()``::
-
-            integerM = integer().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M")
-        """
-        cpy = copy.copy(self)
-        cpy.parseAction = self.parseAction[:]
-        cpy.ignoreExprs = self.ignoreExprs[:]
-        if self.copyDefaultWhiteChars:
-            cpy.whiteChars = ParserElement.DEFAULT_WHITE_CHARS
-        return cpy
-
-    def setName(self, name):
-        """
-        Define name for this expression, makes debugging and exception messages clearer.
-
-        Example::
-
-            Word(nums).parseString("ABC")  # -> Exception: Expected W:(0123...) (at char 0), (line:1, col:1)
-            Word(nums).setName("integer").parseString("ABC")  # -> Exception: Expected integer (at char 0), (line:1, col:1)
-        """
-        self.name = name
-        self.errmsg = "Expected " + self.name
-        if __diag__.enable_debug_on_named_expressions:
-            self.setDebug()
-        return self
-
-    def setResultsName(self, name, listAllMatches=False):
-        """
-        Define name for referencing matching tokens as a nested attribute
-        of the returned parse results.
-        NOTE: this returns a *copy* of the original :class:`ParserElement` object;
-        this is so that the client can define a basic element, such as an
-        integer, and reference it in multiple places with different names.
-
-        You can also set results names using the abbreviated syntax,
-        ``expr("name")`` in place of ``expr.setResultsName("name")``
-        - see :class:`__call__`.
-
-        Example::
-
-            date_str = (integer.setResultsName("year") + '/'
-                        + integer.setResultsName("month") + '/'
-                        + integer.setResultsName("day"))
-
-            # equivalent form:
-            date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
-        """
-        return self._setResultsName(name, listAllMatches)
-
-    def _setResultsName(self, name, listAllMatches=False):
-        newself = self.copy()
-        if name.endswith("*"):
-            name = name[:-1]
-            listAllMatches = True
-        newself.resultsName = name
-        newself.modalResults = not listAllMatches
-        return newself
-
-    def setBreak(self, breakFlag=True):
-        """Method to invoke the Python pdb debugger when this element is
-           about to be parsed. Set ``breakFlag`` to True to enable, False to
-           disable.
-        """
-        if breakFlag:
-            _parseMethod = self._parse
-            def breaker(instring, loc, doActions=True, callPreParse=True):
-                import pdb
-                # this call to pdb.set_trace() is intentional, not a checkin error
-                pdb.set_trace()
-                return _parseMethod(instring, loc, doActions, callPreParse)
-            breaker._originalParseMethod = _parseMethod
-            self._parse = breaker
-        else:
-            if hasattr(self._parse, "_originalParseMethod"):
-                self._parse = self._parse._originalParseMethod
-        return self
-
-    def setParseAction(self, *fns, **kwargs):
-        """
-        Define one or more actions to perform when successfully matching parse element definition.
-        Parse action fn is a callable method with 0-3 arguments, called as ``fn(s, loc, toks)`` ,
-        ``fn(loc, toks)`` , ``fn(toks)`` , or just ``fn()`` , where:
-
-        - s   = the original string being parsed (see note below)
-        - loc = the location of the matching substring
-        - toks = a list of the matched tokens, packaged as a :class:`ParseResults` object
-
-        If the functions in fns modify the tokens, they can return them as the return
-        value from fn, and the modified list of tokens will replace the original.
-        Otherwise, fn does not need to return any value.
-
-        If None is passed as the parse action, all previously added parse actions for this
-        expression are cleared.
-
-        Optional keyword arguments:
-        - callDuringTry = (default= ``False``) indicate if parse action should be run during lookaheads and alternate testing
-
-        Note: the default parsing behavior is to expand tabs in the input string
-        before starting the parsing process.  See :class:`parseString for more
-        information on parsing strings containing ``<TAB>`` s, and suggested
-        methods to maintain a consistent view of the parsed string, the parse
-        location, and line and column positions within the parsed string.
-
-        Example::
-
-            integer = Word(nums)
-            date_str = integer + '/' + integer + '/' + integer
-
-            date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']
-
-            # use parse action to convert to ints at parse time
-            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
-            date_str = integer + '/' + integer + '/' + integer
-
-            # note that integer fields are now ints, not strings
-            date_str.parseString("1999/12/31")  # -> [1999, '/', 12, '/', 31]
-        """
-        if list(fns) == [None,]:
-            self.parseAction = []
-        else:
-            if not all(callable(fn) for fn in fns):
-                raise TypeError("parse actions must be callable")
-            self.parseAction = list(map(_trim_arity, list(fns)))
-            self.callDuringTry = kwargs.get("callDuringTry", False)
-        return self
-
-    def addParseAction(self, *fns, **kwargs):
-        """
-        Add one or more parse actions to expression's list of parse actions. See :class:`setParseAction`.
-
-        See examples in :class:`copy`.
-        """
-        self.parseAction += list(map(_trim_arity, list(fns)))
-        self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False)
-        return self
-
-    def addCondition(self, *fns, **kwargs):
-        """Add a boolean predicate function to expression's list of parse actions. See
-        :class:`setParseAction` for function call signatures. Unlike ``setParseAction``,
-        functions passed to ``addCondition`` need to return boolean success/fail of the condition.
-
-        Optional keyword arguments:
-        - message = define a custom message to be used in the raised exception
-        - fatal   = if True, will raise ParseFatalException to stop parsing immediately; otherwise will raise ParseException
-
-        Example::
-
-            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
-            year_int = integer.copy()
-            year_int.addCondition(lambda toks: toks[0] >= 2000, message="Only support years 2000 and later")
-            date_str = year_int + '/' + integer + '/' + integer
-
-            result = date_str.parseString("1999/12/31")  # -> Exception: Only support years 2000 and later (at char 0), (line:1, col:1)
-        """
-        for fn in fns:
-            self.parseAction.append(conditionAsParseAction(fn, message=kwargs.get('message'),
-                                                           fatal=kwargs.get('fatal', False)))
-
-        self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False)
-        return self
-
-    def setFailAction(self, fn):
-        """Define action to perform if parsing fails at this expression.
-           Fail acton fn is a callable function that takes the arguments
-           ``fn(s, loc, expr, err)`` where:
-           - s = string being parsed
-           - loc = location where expression match was attempted and failed
-           - expr = the parse expression that failed
-           - err = the exception thrown
-           The function returns no value.  It may throw :class:`ParseFatalException`
-           if it is desired to stop parsing immediately."""
-        self.failAction = fn
-        return self
-
-    def _skipIgnorables(self, instring, loc):
-        exprsFound = True
-        while exprsFound:
-            exprsFound = False
-            for e in self.ignoreExprs:
-                try:
-                    while 1:
-                        loc, dummy = e._parse(instring, loc)
-                        exprsFound = True
-                except ParseException:
-                    pass
-        return loc
-
-    def preParse(self, instring, loc):
-        if self.ignoreExprs:
-            loc = self._skipIgnorables(instring, loc)
-
-        if self.skipWhitespace:
-            wt = self.whiteChars
-            instrlen = len(instring)
-            while loc < instrlen and instring[loc] in wt:
-                loc += 1
-
-        return loc
-
-    def parseImpl(self, instring, loc, doActions=True):
-        return loc, []
-
-    def postParse(self, instring, loc, tokenlist):
-        return tokenlist
-
-    # ~ @profile
-    def _parseNoCache(self, instring, loc, doActions=True, callPreParse=True):
-        TRY, MATCH, FAIL = 0, 1, 2
-        debugging = (self.debug)  # and doActions)
-
-        if debugging or self.failAction:
-            # ~ print ("Match", self, "at loc", loc, "(%d, %d)" % (lineno(loc, instring), col(loc, instring)))
-            if self.debugActions[TRY]:
-                self.debugActions[TRY](instring, loc, self)
-            try:
-                if callPreParse and self.callPreparse:
-                    preloc = self.preParse(instring, loc)
-                else:
-                    preloc = loc
-                tokensStart = preloc
-                if self.mayIndexError or preloc >= len(instring):
-                    try:
-                        loc, tokens = self.parseImpl(instring, preloc, doActions)
-                    except IndexError:
-                        raise ParseException(instring, len(instring), self.errmsg, self)
-                else:
-                    loc, tokens = self.parseImpl(instring, preloc, doActions)
-            except Exception as err:
-                # ~ print ("Exception raised:", err)
-                if self.debugActions[FAIL]:
-                    self.debugActions[FAIL](instring, tokensStart, self, err)
-                if self.failAction:
-                    self.failAction(instring, tokensStart, self, err)
-                raise
-        else:
-            if callPreParse and self.callPreparse:
-                preloc = self.preParse(instring, loc)
-            else:
-                preloc = loc
-            tokensStart = preloc
-            if self.mayIndexError or preloc >= len(instring):
-                try:
-                    loc, tokens = self.parseImpl(instring, preloc, doActions)
-                except IndexError:
-                    raise ParseException(instring, len(instring), self.errmsg, self)
-            else:
-                loc, tokens = self.parseImpl(instring, preloc, doActions)
-
-        tokens = self.postParse(instring, loc, tokens)
-
-        retTokens = ParseResults(tokens, self.resultsName, asList=self.saveAsList, modal=self.modalResults)
-        if self.parseAction and (doActions or self.callDuringTry):
-            if debugging:
-                try:
-                    for fn in self.parseAction:
-                        try:
-                            tokens = fn(instring, tokensStart, retTokens)
-                        except IndexError as parse_action_exc:
-                            exc = ParseException("exception raised in parse action")
-                            exc.__cause__ = parse_action_exc
-                            raise exc
-
-                        if tokens is not None and tokens is not retTokens:
-                            retTokens = ParseResults(tokens,
-                                                      self.resultsName,
-                                                      asList=self.saveAsList and isinstance(tokens, (ParseResults, list)),
-                                                      modal=self.modalResults)
-                except Exception as err:
-                    # ~ print "Exception raised in user parse action:", err
-                    if self.debugActions[FAIL]:
-                        self.debugActions[FAIL](instring, tokensStart, self, err)
-                    raise
-            else:
-                for fn in self.parseAction:
-                    try:
-                        tokens = fn(instring, tokensStart, retTokens)
-                    except IndexError as parse_action_exc:
-                        exc = ParseException("exception raised in parse action")
-                        exc.__cause__ = parse_action_exc
-                        raise exc
-
-                    if tokens is not None and tokens is not retTokens:
-                        retTokens = ParseResults(tokens,
-                                                  self.resultsName,
-                                                  asList=self.saveAsList and isinstance(tokens, (ParseResults, list)),
-                                                  modal=self.modalResults)
-        if debugging:
-            # ~ print ("Matched", self, "->", retTokens.asList())
-            if self.debugActions[MATCH]:
-                self.debugActions[MATCH](instring, tokensStart, loc, self, retTokens)
-
-        return loc, retTokens
-
-    def tryParse(self, instring, loc):
-        try:
-            return self._parse(instring, loc, doActions=False)[0]
-        except ParseFatalException:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-    def canParseNext(self, instring, loc):
-        try:
-            self.tryParse(instring, loc)
-        except (ParseException, IndexError):
-            return False
-        else:
-            return True
-
-    class _UnboundedCache(object):
-        def __init__(self):
-            cache = {}
-            self.not_in_cache = not_in_cache = object()
-
-            def get(self, key):
-                return cache.get(key, not_in_cache)
-
-            def set(self, key, value):
-                cache[key] = value
-
-            def clear(self):
-                cache.clear()
-
-            def cache_len(self):
-                return len(cache)
-
-            self.get = types.MethodType(get, self)
-            self.set = types.MethodType(set, self)
-            self.clear = types.MethodType(clear, self)
-            self.__len__ = types.MethodType(cache_len, self)
-
-    if _OrderedDict is not None:
-        class _FifoCache(object):
-            def __init__(self, size):
-                self.not_in_cache = not_in_cache = object()
-
-                cache = _OrderedDict()
-
-                def get(self, key):
-                    return cache.get(key, not_in_cache)
-
-                def set(self, key, value):
-                    cache[key] = value
-                    while len(cache) > size:
-                        try:
-                            cache.popitem(False)
-                        except KeyError:
-                            pass
-
-                def clear(self):
-                    cache.clear()
-
-                def cache_len(self):
-                    return len(cache)
-
-                self.get = types.MethodType(get, self)
-                self.set = types.MethodType(set, self)
-                self.clear = types.MethodType(clear, self)
-                self.__len__ = types.MethodType(cache_len, self)
-
-    else:
-        class _FifoCache(object):
-            def __init__(self, size):
-                self.not_in_cache = not_in_cache = object()
-
-                cache = {}
-                key_fifo = collections.deque([], size)
-
-                def get(self, key):
-                    return cache.get(key, not_in_cache)
-
-                def set(self, key, value):
-                    cache[key] = value
-                    while len(key_fifo) > size:
-                        cache.pop(key_fifo.popleft(), None)
-                    key_fifo.append(key)
-
-                def clear(self):
-                    cache.clear()
-                    key_fifo.clear()
-
-                def cache_len(self):
-                    return len(cache)
-
-                self.get = types.MethodType(get, self)
-                self.set = types.MethodType(set, self)
-                self.clear = types.MethodType(clear, self)
-                self.__len__ = types.MethodType(cache_len, self)
-
-    # argument cache for optimizing repeated calls when backtracking through recursive expressions
-    packrat_cache = {} # this is set later by enabledPackrat(); this is here so that resetCache() doesn't fail
-    packrat_cache_lock = RLock()
-    packrat_cache_stats = [0, 0]
-
-    # this method gets repeatedly called during backtracking with the same arguments -
-    # we can cache these arguments and save ourselves the trouble of re-parsing the contained expression
-    def _parseCache(self, instring, loc, doActions=True, callPreParse=True):
-        HIT, MISS = 0, 1
-        lookup = (self, instring, loc, callPreParse, doActions)
-        with ParserElement.packrat_cache_lock:
-            cache = ParserElement.packrat_cache
-            value = cache.get(lookup)
-            if value is cache.not_in_cache:
-                ParserElement.packrat_cache_stats[MISS] += 1
-                try:
-                    value = self._parseNoCache(instring, loc, doActions, callPreParse)
-                except ParseBaseException as pe:
-                    # cache a copy of the exception, without the traceback
-                    cache.set(lookup, pe.__class__(*pe.args))
-                    raise
-                else:
-                    cache.set(lookup, (value[0], value[1].copy()))
-                    return value
-            else:
-                ParserElement.packrat_cache_stats[HIT] += 1
-                if isinstance(value, Exception):
-                    raise value
-                return value[0], value[1].copy()
-
-    _parse = _parseNoCache
-
-    @staticmethod
-    def resetCache():
-        ParserElement.packrat_cache.clear()
-        ParserElement.packrat_cache_stats[:] = [0] * len(ParserElement.packrat_cache_stats)
-
-    _packratEnabled = False
-    @staticmethod
-    def enablePackrat(cache_size_limit=128):
-        """Enables "packrat" parsing, which adds memoizing to the parsing logic.
-           Repeated parse attempts at the same string location (which happens
-           often in many complex grammars) can immediately return a cached value,
-           instead of re-executing parsing/validating code.  Memoizing is done of
-           both valid results and parsing exceptions.
-
-           Parameters:
-
-           - cache_size_limit - (default= ``128``) - if an integer value is provided
-             will limit the size of the packrat cache; if None is passed, then
-             the cache size will be unbounded; if 0 is passed, the cache will
-             be effectively disabled.
-
-           This speedup may break existing programs that use parse actions that
-           have side-effects.  For this reason, packrat parsing is disabled when
-           you first import pyparsing.  To activate the packrat feature, your
-           program must call the class method :class:`ParserElement.enablePackrat`.
-           For best results, call ``enablePackrat()`` immediately after
-           importing pyparsing.
-
-           Example::
-
-               from pip_api._vendor import pyparsing
-               pyparsing.ParserElement.enablePackrat()
-        """
-        if not ParserElement._packratEnabled:
-            ParserElement._packratEnabled = True
-            if cache_size_limit is None:
-                ParserElement.packrat_cache = ParserElement._UnboundedCache()
-            else:
-                ParserElement.packrat_cache = ParserElement._FifoCache(cache_size_limit)
-            ParserElement._parse = ParserElement._parseCache
-
-    def parseString(self, instring, parseAll=False):
-        """
-        Execute the parse expression with the given string.
-        This is the main interface to the client code, once the complete
-        expression has been built.
-
-        Returns the parsed data as a :class:`ParseResults` object, which may be
-        accessed as a list, or as a dict or object with attributes if the given parser
-        includes results names.
-
-        If you want the grammar to require that the entire input string be
-        successfully parsed, then set ``parseAll`` to True (equivalent to ending
-        the grammar with ``StringEnd()``).
-
-        Note: ``parseString`` implicitly calls ``expandtabs()`` on the input string,
-        in order to report proper column numbers in parse actions.
-        If the input string contains tabs and
-        the grammar uses parse actions that use the ``loc`` argument to index into the
-        string being parsed, you can ensure you have a consistent view of the input
-        string by:
-
-        - calling ``parseWithTabs`` on your grammar before calling ``parseString``
-          (see :class:`parseWithTabs`)
-        - define your parse action using the full ``(s, loc, toks)`` signature, and
-          reference the input string using the parse action's ``s`` argument
-        - explictly expand the tabs in your input string before calling
-          ``parseString``
-
-        Example::
-
-            Word('a').parseString('aaaaabaaa')  # -> ['aaaaa']
-            Word('a').parseString('aaaaabaaa', parseAll=True)  # -> Exception: Expected end of text
-        """
-        ParserElement.resetCache()
-        if not self.streamlined:
-            self.streamline()
-            # ~ self.saveAsList = True
-        for e in self.ignoreExprs:
-            e.streamline()
-        if not self.keepTabs:
-            instring = instring.expandtabs()
-        try:
-            loc, tokens = self._parse(instring, 0)
-            if parseAll:
-                loc = self.preParse(instring, loc)
-                se = Empty() + StringEnd()
-                se._parse(instring, loc)
-        except ParseBaseException as exc:
-            if ParserElement.verbose_stacktrace:
-                raise
-            else:
-                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
-                if getattr(exc, '__traceback__', None) is not None:
-                    exc.__traceback__ = self._trim_traceback(exc.__traceback__)
-                raise exc
-        else:
-            return tokens
-
-    def scanString(self, instring, maxMatches=_MAX_INT, overlap=False):
-        """
-        Scan the input string for expression matches.  Each match will return the
-        matching tokens, start location, and end location.  May be called with optional
-        ``maxMatches`` argument, to clip scanning after 'n' matches are found.  If
-        ``overlap`` is specified, then overlapping matches will be reported.
-
-        Note that the start and end locations are reported relative to the string
-        being parsed.  See :class:`parseString` for more information on parsing
-        strings with embedded tabs.
-
-        Example::
-
-            source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
-            print(source)
-            for tokens, start, end in Word(alphas).scanString(source):
-                print(' '*start + '^'*(end-start))
-                print(' '*start + tokens[0])
-
-        prints::
-
-            sldjf123lsdjjkf345sldkjf879lkjsfd987
-            ^^^^^
-            sldjf
-                    ^^^^^^^
-                    lsdjjkf
-                              ^^^^^^
-                              sldkjf
-                                       ^^^^^^
-                                       lkjsfd
-        """
-        if not self.streamlined:
-            self.streamline()
-        for e in self.ignoreExprs:
-            e.streamline()
-
-        if not self.keepTabs:
-            instring = _ustr(instring).expandtabs()
-        instrlen = len(instring)
-        loc = 0
-        preparseFn = self.preParse
-        parseFn = self._parse
-        ParserElement.resetCache()
-        matches = 0
-        try:
-            while loc <= instrlen and matches < maxMatches:
-                try:
-                    preloc = preparseFn(instring, loc)
-                    nextLoc, tokens = parseFn(instring, preloc, callPreParse=False)
-                except ParseException:
-                    loc = preloc + 1
-                else:
-                    if nextLoc > loc:
-                        matches += 1
-                        yield tokens, preloc, nextLoc
-                        if overlap:
-                            nextloc = preparseFn(instring, loc)
-                            if nextloc > loc:
-                                loc = nextLoc
-                            else:
-                                loc += 1
-                        else:
-                            loc = nextLoc
-                    else:
-                        loc = preloc + 1
-        except ParseBaseException as exc:
-            if ParserElement.verbose_stacktrace:
-                raise
-            else:
-                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
-                if getattr(exc, '__traceback__', None) is not None:
-                    exc.__traceback__ = self._trim_traceback(exc.__traceback__)
-                raise exc
-
-    def transformString(self, instring):
-        """
-        Extension to :class:`scanString`, to modify matching text with modified tokens that may
-        be returned from a parse action.  To use ``transformString``, define a grammar and
-        attach a parse action to it that modifies the returned token list.
-        Invoking ``transformString()`` on a target string will then scan for matches,
-        and replace the matched text patterns according to the logic in the parse
-        action.  ``transformString()`` returns the resulting transformed string.
-
-        Example::
-
-            wd = Word(alphas)
-            wd.setParseAction(lambda toks: toks[0].title())
-
-            print(wd.transformString("now is the winter of our discontent made glorious summer by this sun of york."))
-
-        prints::
-
-            Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York.
-        """
-        out = []
-        lastE = 0
-        # force preservation of <TAB>s, to minimize unwanted transformation of string, and to
-        # keep string locs straight between transformString and scanString
-        self.keepTabs = True
-        try:
-            for t, s, e in self.scanString(instring):
-                out.append(instring[lastE:s])
-                if t:
-                    if isinstance(t, ParseResults):
-                        out += t.asList()
-                    elif isinstance(t, list):
-                        out += t
-                    else:
-                        out.append(t)
-                lastE = e
-            out.append(instring[lastE:])
-            out = [o for o in out if o]
-            return "".join(map(_ustr, _flatten(out)))
-        except ParseBaseException as exc:
-            if ParserElement.verbose_stacktrace:
-                raise
-            else:
-                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
-                if getattr(exc, '__traceback__', None) is not None:
-                    exc.__traceback__ = self._trim_traceback(exc.__traceback__)
-                raise exc
-
-    def searchString(self, instring, maxMatches=_MAX_INT):
-        """
-        Another extension to :class:`scanString`, simplifying the access to the tokens found
-        to match the given parse expression.  May be called with optional
-        ``maxMatches`` argument, to clip searching after 'n' matches are found.
-
-        Example::
-
-            # a capitalized word starts with an uppercase letter, followed by zero or more lowercase letters
-            cap_word = Word(alphas.upper(), alphas.lower())
-
-            print(cap_word.searchString("More than Iron, more than Lead, more than Gold I need Electricity"))
-
-            # the sum() builtin can be used to merge results into a single ParseResults object
-            print(sum(cap_word.searchString("More than Iron, more than Lead, more than Gold I need Electricity")))
-
-        prints::
-
-            [['More'], ['Iron'], ['Lead'], ['Gold'], ['I'], ['Electricity']]
-            ['More', 'Iron', 'Lead', 'Gold', 'I', 'Electricity']
-        """
-        try:
-            return ParseResults([t for t, s, e in self.scanString(instring, maxMatches)])
-        except ParseBaseException as exc:
-            if ParserElement.verbose_stacktrace:
-                raise
-            else:
-                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
-                if getattr(exc, '__traceback__', None) is not None:
-                    exc.__traceback__ = self._trim_traceback(exc.__traceback__)
-                raise exc
-
-    def split(self, instring, maxsplit=_MAX_INT, includeSeparators=False):
-        """
-        Generator method to split a string using the given expression as a separator.
-        May be called with optional ``maxsplit`` argument, to limit the number of splits;
-        and the optional ``includeSeparators`` argument (default= ``False``), if the separating
-        matching text should be included in the split results.
-
-        Example::
-
-            punc = oneOf(list(".,;:/-!?"))
-            print(list(punc.split("This, this?, this sentence, is badly punctuated!")))
-
-        prints::
-
-            ['This', ' this', '', ' this sentence', ' is badly punctuated', '']
-        """
-        splits = 0
-        last = 0
-        for t, s, e in self.scanString(instring, maxMatches=maxsplit):
-            yield instring[last:s]
-            if includeSeparators:
-                yield t[0]
-            last = e
-        yield instring[last:]
-
-    def __add__(self, other):
-        """
-        Implementation of + operator - returns :class:`And`. Adding strings to a ParserElement
-        converts them to :class:`Literal`s by default.
-
-        Example::
-
-            greet = Word(alphas) + "," + Word(alphas) + "!"
-            hello = "Hello, World!"
-            print (hello, "->", greet.parseString(hello))
-
-        prints::
-
-            Hello, World! -> ['Hello', ',', 'World', '!']
-
-        ``...`` may be used as a parse expression as a short form of :class:`SkipTo`.
-
-            Literal('start') + ... + Literal('end')
-
-        is equivalent to:
-
-            Literal('start') + SkipTo('end')("_skipped*") + Literal('end')
-
-        Note that the skipped text is returned with '_skipped' as a results name,
-        and to support having multiple skips in the same parser, the value returned is
-        a list of all skipped text.
-        """
-        if other is Ellipsis:
-            return _PendingSkip(self)
-
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return And([self, other])
-
-    def __radd__(self, other):
-        """
-        Implementation of + operator when left operand is not a :class:`ParserElement`
-        """
-        if other is Ellipsis:
-            return SkipTo(self)("_skipped*") + self
-
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return other + self
-
-    def __sub__(self, other):
-        """
-        Implementation of - operator, returns :class:`And` with error stop
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return self + And._ErrorStop() + other
-
-    def __rsub__(self, other):
-        """
-        Implementation of - operator when left operand is not a :class:`ParserElement`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return other - self
-
-    def __mul__(self, other):
-        """
-        Implementation of * operator, allows use of ``expr * 3`` in place of
-        ``expr + expr + expr``.  Expressions may also me multiplied by a 2-integer
-        tuple, similar to ``{min, max}`` multipliers in regular expressions.  Tuples
-        may also include ``None`` as in:
-         - ``expr*(n, None)`` or ``expr*(n, )`` is equivalent
-              to ``expr*n + ZeroOrMore(expr)``
-              (read as "at least n instances of ``expr``")
-         - ``expr*(None, n)`` is equivalent to ``expr*(0, n)``
-              (read as "0 to n instances of ``expr``")
-         - ``expr*(None, None)`` is equivalent to ``ZeroOrMore(expr)``
-         - ``expr*(1, None)`` is equivalent to ``OneOrMore(expr)``
-
-        Note that ``expr*(None, n)`` does not raise an exception if
-        more than n exprs exist in the input stream; that is,
-        ``expr*(None, n)`` does not enforce a maximum number of expr
-        occurrences.  If this behavior is desired, then write
-        ``expr*(None, n) + ~expr``
-        """
-        if other is Ellipsis:
-            other = (0, None)
-        elif isinstance(other, tuple) and other[:1] == (Ellipsis,):
-            other = ((0, ) + other[1:] + (None,))[:2]
-
-        if isinstance(other, int):
-            minElements, optElements = other, 0
-        elif isinstance(other, tuple):
-            other = tuple(o if o is not Ellipsis else None for o in other)
-            other = (other + (None, None))[:2]
-            if other[0] is None:
-                other = (0, other[1])
-            if isinstance(other[0], int) and other[1] is None:
-                if other[0] == 0:
-                    return ZeroOrMore(self)
-                if other[0] == 1:
-                    return OneOrMore(self)
-                else:
-                    return self * other[0] + ZeroOrMore(self)
-            elif isinstance(other[0], int) and isinstance(other[1], int):
-                minElements, optElements = other
-                optElements -= minElements
-            else:
-                raise TypeError("cannot multiply 'ParserElement' and ('%s', '%s') objects", type(other[0]), type(other[1]))
-        else:
-            raise TypeError("cannot multiply 'ParserElement' and '%s' objects", type(other))
-
-        if minElements < 0:
-            raise ValueError("cannot multiply ParserElement by negative value")
-        if optElements < 0:
-            raise ValueError("second tuple value must be greater or equal to first tuple value")
-        if minElements == optElements == 0:
-            raise ValueError("cannot multiply ParserElement by 0 or (0, 0)")
-
-        if optElements:
-            def makeOptionalList(n):
-                if n > 1:
-                    return Optional(self + makeOptionalList(n - 1))
-                else:
-                    return Optional(self)
-            if minElements:
-                if minElements == 1:
-                    ret = self + makeOptionalList(optElements)
-                else:
-                    ret = And([self] * minElements) + makeOptionalList(optElements)
-            else:
-                ret = makeOptionalList(optElements)
-        else:
-            if minElements == 1:
-                ret = self
-            else:
-                ret = And([self] * minElements)
-        return ret
-
-    def __rmul__(self, other):
-        return self.__mul__(other)
-
-    def __or__(self, other):
-        """
-        Implementation of | operator - returns :class:`MatchFirst`
-        """
-        if other is Ellipsis:
-            return _PendingSkip(self, must_skip=True)
-
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return MatchFirst([self, other])
-
-    def __ror__(self, other):
-        """
-        Implementation of | operator when left operand is not a :class:`ParserElement`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return other | self
-
-    def __xor__(self, other):
-        """
-        Implementation of ^ operator - returns :class:`Or`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return Or([self, other])
-
-    def __rxor__(self, other):
-        """
-        Implementation of ^ operator when left operand is not a :class:`ParserElement`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return other ^ self
-
-    def __and__(self, other):
-        """
-        Implementation of & operator - returns :class:`Each`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return Each([self, other])
-
-    def __rand__(self, other):
-        """
-        Implementation of & operator when left operand is not a :class:`ParserElement`
-        """
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        if not isinstance(other, ParserElement):
-            warnings.warn("Cannot combine element of type %s with ParserElement" % type(other),
-                          SyntaxWarning, stacklevel=2)
-            return None
-        return other & self
-
-    def __invert__(self):
-        """
-        Implementation of ~ operator - returns :class:`NotAny`
-        """
-        return NotAny(self)
-
-    def __iter__(self):
-        # must implement __iter__ to override legacy use of sequential access to __getitem__ to
-        # iterate over a sequence
-        raise TypeError('%r object is not iterable' % self.__class__.__name__)
-
-    def __getitem__(self, key):
-        """
-        use ``[]`` indexing notation as a short form for expression repetition:
-         - ``expr[n]`` is equivalent to ``expr*n``
-         - ``expr[m, n]`` is equivalent to ``expr*(m, n)``
-         - ``expr[n, ...]`` or ``expr[n,]`` is equivalent
-              to ``expr*n + ZeroOrMore(expr)``
-              (read as "at least n instances of ``expr``")
-         - ``expr[..., n]`` is equivalent to ``expr*(0, n)``
-              (read as "0 to n instances of ``expr``")
-         - ``expr[...]`` and ``expr[0, ...]`` are equivalent to ``ZeroOrMore(expr)``
-         - ``expr[1, ...]`` is equivalent to ``OneOrMore(expr)``
-         ``None`` may be used in place of ``...``.
-
-        Note that ``expr[..., n]`` and ``expr[m, n]``do not raise an exception
-        if more than ``n`` ``expr``s exist in the input stream.  If this behavior is
-        desired, then write ``expr[..., n] + ~expr``.
-       """
-
-        # convert single arg keys to tuples
-        try:
-            if isinstance(key, str):
-                key = (key,)
-            iter(key)
-        except TypeError:
-            key = (key, key)
-
-        if len(key) > 2:
-            warnings.warn("only 1 or 2 index arguments supported ({0}{1})".format(key[:5],
-                                                                                '... [{0}]'.format(len(key))
-                                                                                if len(key) > 5 else ''))
-
-        # clip to 2 elements
-        ret = self * tuple(key[:2])
-        return ret
-
-    def __call__(self, name=None):
-        """
-        Shortcut for :class:`setResultsName`, with ``listAllMatches=False``.
-
-        If ``name`` is given with a trailing ``'*'`` character, then ``listAllMatches`` will be
-        passed as ``True``.
-
-        If ``name` is omitted, same as calling :class:`copy`.
-
-        Example::
-
-            # these are equivalent
-            userdata = Word(alphas).setResultsName("name") + Word(nums + "-").setResultsName("socsecno")
-            userdata = Word(alphas)("name") + Word(nums + "-")("socsecno")
-        """
-        if name is not None:
-            return self._setResultsName(name)
-        else:
-            return self.copy()
-
-    def suppress(self):
-        """
-        Suppresses the output of this :class:`ParserElement`; useful to keep punctuation from
-        cluttering up returned output.
-        """
-        return Suppress(self)
-
-    def leaveWhitespace(self):
-        """
-        Disables the skipping of whitespace before matching the characters in the
-        :class:`ParserElement`'s defined pattern.  This is normally only used internally by
-        the pyparsing module, but may be needed in some whitespace-sensitive grammars.
-        """
-        self.skipWhitespace = False
-        return self
-
-    def setWhitespaceChars(self, chars):
-        """
-        Overrides the default whitespace chars
-        """
-        self.skipWhitespace = True
-        self.whiteChars = chars
-        self.copyDefaultWhiteChars = False
-        return self
-
-    def parseWithTabs(self):
-        """
-        Overrides default behavior to expand ``<TAB>``s to spaces before parsing the input string.
-        Must be called before ``parseString`` when the input grammar contains elements that
-        match ``<TAB>`` characters.
-        """
-        self.keepTabs = True
-        return self
-
-    def ignore(self, other):
-        """
-        Define expression to be ignored (e.g., comments) while doing pattern
-        matching; may be called repeatedly, to define multiple comment or other
-        ignorable patterns.
-
-        Example::
-
-            patt = OneOrMore(Word(alphas))
-            patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj']
-
-            patt.ignore(cStyleComment)
-            patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd']
-        """
-        if isinstance(other, basestring):
-            other = Suppress(other)
-
-        if isinstance(other, Suppress):
-            if other not in self.ignoreExprs:
-                self.ignoreExprs.append(other)
-        else:
-            self.ignoreExprs.append(Suppress(other.copy()))
-        return self
-
-    def setDebugActions(self, startAction, successAction, exceptionAction):
-        """
-        Enable display of debugging messages while doing pattern matching.
-        """
-        self.debugActions = (startAction or _defaultStartDebugAction,
-                             successAction or _defaultSuccessDebugAction,
-                             exceptionAction or _defaultExceptionDebugAction)
-        self.debug = True
-        return self
-
-    def setDebug(self, flag=True):
-        """
-        Enable display of debugging messages while doing pattern matching.
-        Set ``flag`` to True to enable, False to disable.
-
-        Example::
-
-            wd = Word(alphas).setName("alphaword")
-            integer = Word(nums).setName("numword")
-            term = wd | integer
-
-            # turn on debugging for wd
-            wd.setDebug()
-
-            OneOrMore(term).parseString("abc 123 xyz 890")
-
-        prints::
-
-            Match alphaword at loc 0(1,1)
-            Matched alphaword -> ['abc']
-            Match alphaword at loc 3(1,4)
-            Exception raised:Expected alphaword (at char 4), (line:1, col:5)
-            Match alphaword at loc 7(1,8)
-            Matched alphaword -> ['xyz']
-            Match alphaword at loc 11(1,12)
-            Exception raised:Expected alphaword (at char 12), (line:1, col:13)
-            Match alphaword at loc 15(1,16)
-            Exception raised:Expected alphaword (at char 15), (line:1, col:16)
-
-        The output shown is that produced by the default debug actions - custom debug actions can be
-        specified using :class:`setDebugActions`. Prior to attempting
-        to match the ``wd`` expression, the debugging message ``"Match <exprname> at loc <n>(<line>,<col>)"``
-        is shown. Then if the parse succeeds, a ``"Matched"`` message is shown, or an ``"Exception raised"``
-        message is shown. Also note the use of :class:`setName` to assign a human-readable name to the expression,
-        which makes debugging and exception messages easier to understand - for instance, the default
-        name created for the :class:`Word` expression without calling ``setName`` is ``"W:(ABCD...)"``.
-        """
-        if flag:
-            self.setDebugActions(_defaultStartDebugAction, _defaultSuccessDebugAction, _defaultExceptionDebugAction)
-        else:
-            self.debug = False
-        return self
-
-    def __str__(self):
-        return self.name
-
-    def __repr__(self):
-        return _ustr(self)
-
-    def streamline(self):
-        self.streamlined = True
-        self.strRepr = None
-        return self
-
-    def checkRecursion(self, parseElementList):
-        pass
-
-    def validate(self, validateTrace=None):
-        """
-        Check defined expressions for valid structure, check for infinite recursive definitions.
-        """
-        self.checkRecursion([])
-
-    def parseFile(self, file_or_filename, parseAll=False):
-        """
-        Execute the parse expression on the given file or filename.
-        If a filename is specified (instead of a file object),
-        the entire file is opened, read, and closed before parsing.
-        """
-        try:
-            file_contents = file_or_filename.read()
-        except AttributeError:
-            with open(file_or_filename, "r") as f:
-                file_contents = f.read()
-        try:
-            return self.parseString(file_contents, parseAll)
-        except ParseBaseException as exc:
-            if ParserElement.verbose_stacktrace:
-                raise
-            else:
-                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
-                if getattr(exc, '__traceback__', None) is not None:
-                    exc.__traceback__ = self._trim_traceback(exc.__traceback__)
-                raise exc
-
-    def __eq__(self, other):
-        if self is other:
-            return True
-        elif isinstance(other, basestring):
-            return self.matches(other)
-        elif isinstance(other, ParserElement):
-            return vars(self) == vars(other)
-        return False
-
-    def __ne__(self, other):
-        return not (self == other)
-
-    def __hash__(self):
-        return id(self)
-
-    def __req__(self, other):
-        return self == other
-
-    def __rne__(self, other):
-        return not (self == other)
-
-    def matches(self, testString, parseAll=True):
-        """
-        Method for quick testing of a parser against a test string. Good for simple
-        inline microtests of sub expressions while building up larger parser.
-
-        Parameters:
-         - testString - to test against this expression for a match
-         - parseAll - (default= ``True``) - flag to pass to :class:`parseString` when running tests
-
-        Example::
-
-            expr = Word(nums)
-            assert expr.matches("100")
-        """
-        try:
-            self.parseString(_ustr(testString), parseAll=parseAll)
-            return True
-        except ParseBaseException:
-            return False
-
-    def runTests(self, tests, parseAll=True, comment='#',
-                 fullDump=True, printResults=True, failureTests=False, postParse=None,
-                 file=None):
-        """
-        Execute the parse expression on a series of test strings, showing each
-        test, the parsed results or where the parse failed. Quick and easy way to
-        run a parse expression against a list of sample strings.
-
-        Parameters:
-         - tests - a list of separate test strings, or a multiline string of test strings
-         - parseAll - (default= ``True``) - flag to pass to :class:`parseString` when running tests
-         - comment - (default= ``'#'``) - expression for indicating embedded comments in the test
-              string; pass None to disable comment filtering
-         - fullDump - (default= ``True``) - dump results as list followed by results names in nested outline;
-              if False, only dump nested list
-         - printResults - (default= ``True``) prints test output to stdout
-         - failureTests - (default= ``False``) indicates if these tests are expected to fail parsing
-         - postParse - (default= ``None``) optional callback for successful parse results; called as
-              `fn(test_string, parse_results)` and returns a string to be added to the test output
-         - file - (default=``None``) optional file-like object to which test output will be written;
-              if None, will default to ``sys.stdout``
-
-        Returns: a (success, results) tuple, where success indicates that all tests succeeded
-        (or failed if ``failureTests`` is True), and the results contain a list of lines of each
-        test's output
-
-        Example::
-
-            number_expr = pyparsing_common.number.copy()
-
-            result = number_expr.runTests('''
-                # unsigned integer
-                100
-                # negative integer
-                -100
-                # float with scientific notation
-                6.02e23
-                # integer with scientific notation
-                1e-12
-                ''')
-            print("Success" if result[0] else "Failed!")
-
-            result = number_expr.runTests('''
-                # stray character
-                100Z
-                # missing leading digit before '.'
-                -.100
-                # too many '.'
-                3.14.159
-                ''', failureTests=True)
-            print("Success" if result[0] else "Failed!")
-
-        prints::
-
-            # unsigned integer
-            100
-            [100]
-
-            # negative integer
-            -100
-            [-100]
-
-            # float with scientific notation
-            6.02e23
-            [6.02e+23]
-
-            # integer with scientific notation
-            1e-12
-            [1e-12]
-
-            Success
-
-            # stray character
-            100Z
-               ^
-            FAIL: Expected end of text (at char 3), (line:1, col:4)
-
-            # missing leading digit before '.'
-            -.100
-            ^
-            FAIL: Expected {real number with scientific notation | real number | signed integer} (at char 0), (line:1, col:1)
-
-            # too many '.'
-            3.14.159
-                ^
-            FAIL: Expected end of text (at char 4), (line:1, col:5)
-
-            Success
-
-        Each test string must be on a single line. If you want to test a string that spans multiple
-        lines, create a test like this::
-
-            expr.runTest(r"this is a test\\n of strings that spans \\n 3 lines")
-
-        (Note that this is a raw string literal, you must include the leading 'r'.)
-        """
-        if isinstance(tests, basestring):
-            tests = list(map(str.strip, tests.rstrip().splitlines()))
-        if isinstance(comment, basestring):
-            comment = Literal(comment)
-        if file is None:
-            file = sys.stdout
-        print_ = file.write
-
-        allResults = []
-        comments = []
-        success = True
-        NL = Literal(r'\n').addParseAction(replaceWith('\n')).ignore(quotedString)
-        BOM = u'\ufeff'
-        for t in tests:
-            if comment is not None and comment.matches(t, False) or comments and not t:
-                comments.append(t)
-                continue
-            if not t:
-                continue
-            out = ['\n' + '\n'.join(comments) if comments else '', t]
-            comments = []
-            try:
-                # convert newline marks to actual newlines, and strip leading BOM if present
-                t = NL.transformString(t.lstrip(BOM))
-                result = self.parseString(t, parseAll=parseAll)
-            except ParseBaseException as pe:
-                fatal = "(FATAL)" if isinstance(pe, ParseFatalException) else ""
-                if '\n' in t:
-                    out.append(line(pe.loc, t))
-                    out.append(' ' * (col(pe.loc, t) - 1) + '^' + fatal)
-                else:
-                    out.append(' ' * pe.loc + '^' + fatal)
-                out.append("FAIL: " + str(pe))
-                success = success and failureTests
-                result = pe
-            except Exception as exc:
-                out.append("FAIL-EXCEPTION: " + str(exc))
-                success = success and failureTests
-                result = exc
-            else:
-                success = success and not failureTests
-                if postParse is not None:
-                    try:
-                        pp_value = postParse(t, result)
-                        if pp_value is not None:
-                            if isinstance(pp_value, ParseResults):
-                                out.append(pp_value.dump())
-                            else:
-                                out.append(str(pp_value))
-                        else:
-                            out.append(result.dump())
-                    except Exception as e:
-                        out.append(result.dump(full=fullDump))
-                        out.append("{0} failed: {1}: {2}".format(postParse.__name__, type(e).__name__, e))
-                else:
-                    out.append(result.dump(full=fullDump))
-
-            if printResults:
-                if fullDump:
-                    out.append('')
-                print_('\n'.join(out))
-
-            allResults.append((t, result))
-
-        return success, allResults
-
-
-class _PendingSkip(ParserElement):
-    # internal placeholder class to hold a place were '...' is added to a parser element,
-    # once another ParserElement is added, this placeholder will be replaced with a SkipTo
-    def __init__(self, expr, must_skip=False):
-        super(_PendingSkip, self).__init__()
-        self.strRepr = str(expr + Empty()).replace('Empty', '...')
-        self.name = self.strRepr
-        self.anchor = expr
-        self.must_skip = must_skip
-
-    def __add__(self, other):
-        skipper = SkipTo(other).setName("...")("_skipped*")
-        if self.must_skip:
-            def must_skip(t):
-                if not t._skipped or t._skipped.asList() == ['']:
-                    del t[0]
-                    t.pop("_skipped", None)
-            def show_skip(t):
-                if t._skipped.asList()[-1:] == ['']:
-                    skipped = t.pop('_skipped')
-                    t['_skipped'] = 'missing <' + repr(self.anchor) + '>'
-            return (self.anchor + skipper().addParseAction(must_skip)
-                    | skipper().addParseAction(show_skip)) + other
-
-        return self.anchor + skipper + other
-
-    def __repr__(self):
-        return self.strRepr
-
-    def parseImpl(self, *args):
-        raise Exception("use of `...` expression without following SkipTo target expression")
-
-
-class Token(ParserElement):
-    """Abstract :class:`ParserElement` subclass, for defining atomic
-    matching patterns.
-    """
-    def __init__(self):
-        super(Token, self).__init__(savelist=False)
-
-
-class Empty(Token):
-    """An empty token, will always match.
-    """
-    def __init__(self):
-        super(Empty, self).__init__()
-        self.name = "Empty"
-        self.mayReturnEmpty = True
-        self.mayIndexError = False
-
-
-class NoMatch(Token):
-    """A token that will never match.
-    """
-    def __init__(self):
-        super(NoMatch, self).__init__()
-        self.name = "NoMatch"
-        self.mayReturnEmpty = True
-        self.mayIndexError = False
-        self.errmsg = "Unmatchable token"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        raise ParseException(instring, loc, self.errmsg, self)
-
-
-class Literal(Token):
-    """Token to exactly match a specified string.
-
-    Example::
-
-        Literal('blah').parseString('blah')  # -> ['blah']
-        Literal('blah').parseString('blahfooblah')  # -> ['blah']
-        Literal('blah').parseString('bla')  # -> Exception: Expected "blah"
-
-    For case-insensitive matching, use :class:`CaselessLiteral`.
-
-    For keyword matching (force word break before and after the matched string),
-    use :class:`Keyword` or :class:`CaselessKeyword`.
-    """
-    def __init__(self, matchString):
-        super(Literal, self).__init__()
-        self.match = matchString
-        self.matchLen = len(matchString)
-        try:
-            self.firstMatchChar = matchString[0]
-        except IndexError:
-            warnings.warn("null string passed to Literal; use Empty() instead",
-                            SyntaxWarning, stacklevel=2)
-            self.__class__ = Empty
-        self.name = '"%s"' % _ustr(self.match)
-        self.errmsg = "Expected " + self.name
-        self.mayReturnEmpty = False
-        self.mayIndexError = False
-
-        # Performance tuning: modify __class__ to select
-        # a parseImpl optimized for single-character check
-        if self.matchLen == 1 and type(self) is Literal:
-            self.__class__ = _SingleCharLiteral
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc] == self.firstMatchChar and instring.startswith(self.match, loc):
-            return loc + self.matchLen, self.match
-        raise ParseException(instring, loc, self.errmsg, self)
-
-class _SingleCharLiteral(Literal):
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc] == self.firstMatchChar:
-            return loc + 1, self.match
-        raise ParseException(instring, loc, self.errmsg, self)
-
-_L = Literal
-ParserElement._literalStringClass = Literal
-
-class Keyword(Token):
-    """Token to exactly match a specified string as a keyword, that is,
-    it must be immediately followed by a non-keyword character.  Compare
-    with :class:`Literal`:
-
-     - ``Literal("if")`` will match the leading ``'if'`` in
-       ``'ifAndOnlyIf'``.
-     - ``Keyword("if")`` will not; it will only match the leading
-       ``'if'`` in ``'if x=1'``, or ``'if(y==2)'``
-
-    Accepts two optional constructor arguments in addition to the
-    keyword string:
-
-     - ``identChars`` is a string of characters that would be valid
-       identifier characters, defaulting to all alphanumerics + "_" and
-       "$"
-     - ``caseless`` allows case-insensitive matching, default is ``False``.
-
-    Example::
-
-        Keyword("start").parseString("start")  # -> ['start']
-        Keyword("start").parseString("starting")  # -> Exception
-
-    For case-insensitive matching, use :class:`CaselessKeyword`.
-    """
-    DEFAULT_KEYWORD_CHARS = alphanums + "_$"
-
-    def __init__(self, matchString, identChars=None, caseless=False):
-        super(Keyword, self).__init__()
-        if identChars is None:
-            identChars = Keyword.DEFAULT_KEYWORD_CHARS
-        self.match = matchString
-        self.matchLen = len(matchString)
-        try:
-            self.firstMatchChar = matchString[0]
-        except IndexError:
-            warnings.warn("null string passed to Keyword; use Empty() instead",
-                          SyntaxWarning, stacklevel=2)
-        self.name = '"%s"' % self.match
-        self.errmsg = "Expected " + self.name
-        self.mayReturnEmpty = False
-        self.mayIndexError = False
-        self.caseless = caseless
-        if caseless:
-            self.caselessmatch = matchString.upper()
-            identChars = identChars.upper()
-        self.identChars = set(identChars)
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if self.caseless:
-            if ((instring[loc:loc + self.matchLen].upper() == self.caselessmatch)
-                    and (loc >= len(instring) - self.matchLen
-                         or instring[loc + self.matchLen].upper() not in self.identChars)
-                    and (loc == 0
-                         or instring[loc - 1].upper() not in self.identChars)):
-                return loc + self.matchLen, self.match
-
-        else:
-            if instring[loc] == self.firstMatchChar:
-                if ((self.matchLen == 1 or instring.startswith(self.match, loc))
-                        and (loc >= len(instring) - self.matchLen
-                             or instring[loc + self.matchLen] not in self.identChars)
-                        and (loc == 0 or instring[loc - 1] not in self.identChars)):
-                    return loc + self.matchLen, self.match
-
-        raise ParseException(instring, loc, self.errmsg, self)
-
-    def copy(self):
-        c = super(Keyword, self).copy()
-        c.identChars = Keyword.DEFAULT_KEYWORD_CHARS
-        return c
-
-    @staticmethod
-    def setDefaultKeywordChars(chars):
-        """Overrides the default Keyword chars
-        """
-        Keyword.DEFAULT_KEYWORD_CHARS = chars
-
-class CaselessLiteral(Literal):
-    """Token to match a specified string, ignoring case of letters.
-    Note: the matched results will always be in the case of the given
-    match string, NOT the case of the input text.
-
-    Example::
-
-        OneOrMore(CaselessLiteral("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD', 'CMD']
-
-    (Contrast with example for :class:`CaselessKeyword`.)
-    """
-    def __init__(self, matchString):
-        super(CaselessLiteral, self).__init__(matchString.upper())
-        # Preserve the defining literal.
-        self.returnString = matchString
-        self.name = "'%s'" % self.returnString
-        self.errmsg = "Expected " + self.name
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc:loc + self.matchLen].upper() == self.match:
-            return loc + self.matchLen, self.returnString
-        raise ParseException(instring, loc, self.errmsg, self)
-
-class CaselessKeyword(Keyword):
-    """
-    Caseless version of :class:`Keyword`.
-
-    Example::
-
-        OneOrMore(CaselessKeyword("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD']
-
-    (Contrast with example for :class:`CaselessLiteral`.)
-    """
-    def __init__(self, matchString, identChars=None):
-        super(CaselessKeyword, self).__init__(matchString, identChars, caseless=True)
-
-class CloseMatch(Token):
-    """A variation on :class:`Literal` which matches "close" matches,
-    that is, strings with at most 'n' mismatching characters.
-    :class:`CloseMatch` takes parameters:
-
-     - ``match_string`` - string to be matched
-     - ``maxMismatches`` - (``default=1``) maximum number of
-       mismatches allowed to count as a match
-
-    The results from a successful parse will contain the matched text
-    from the input string and the following named results:
-
-     - ``mismatches`` - a list of the positions within the
-       match_string where mismatches were found
-     - ``original`` - the original match_string used to compare
-       against the input string
-
-    If ``mismatches`` is an empty list, then the match was an exact
-    match.
-
-    Example::
-
-        patt = CloseMatch("ATCATCGAATGGA")
-        patt.parseString("ATCATCGAAXGGA") # -> (['ATCATCGAAXGGA'], {'mismatches': [[9]], 'original': ['ATCATCGAATGGA']})
-        patt.parseString("ATCAXCGAAXGGA") # -> Exception: Expected 'ATCATCGAATGGA' (with up to 1 mismatches) (at char 0), (line:1, col:1)
-
-        # exact match
-        patt.parseString("ATCATCGAATGGA") # -> (['ATCATCGAATGGA'], {'mismatches': [[]], 'original': ['ATCATCGAATGGA']})
-
-        # close match allowing up to 2 mismatches
-        patt = CloseMatch("ATCATCGAATGGA", maxMismatches=2)
-        patt.parseString("ATCAXCGAAXGGA") # -> (['ATCAXCGAAXGGA'], {'mismatches': [[4, 9]], 'original': ['ATCATCGAATGGA']})
-    """
-    def __init__(self, match_string, maxMismatches=1):
-        super(CloseMatch, self).__init__()
-        self.name = match_string
-        self.match_string = match_string
-        self.maxMismatches = maxMismatches
-        self.errmsg = "Expected %r (with up to %d mismatches)" % (self.match_string, self.maxMismatches)
-        self.mayIndexError = False
-        self.mayReturnEmpty = False
-
-    def parseImpl(self, instring, loc, doActions=True):
-        start = loc
-        instrlen = len(instring)
-        maxloc = start + len(self.match_string)
-
-        if maxloc <= instrlen:
-            match_string = self.match_string
-            match_stringloc = 0
-            mismatches = []
-            maxMismatches = self.maxMismatches
-
-            for match_stringloc, s_m in enumerate(zip(instring[loc:maxloc], match_string)):
-                src, mat = s_m
-                if src != mat:
-                    mismatches.append(match_stringloc)
-                    if len(mismatches) > maxMismatches:
-                        break
-            else:
-                loc = match_stringloc + 1
-                results = ParseResults([instring[start:loc]])
-                results['original'] = match_string
-                results['mismatches'] = mismatches
-                return loc, results
-
-        raise ParseException(instring, loc, self.errmsg, self)
-
-
-class Word(Token):
-    """Token for matching words composed of allowed character sets.
-    Defined with string containing all allowed initial characters, an
-    optional string containing allowed body characters (if omitted,
-    defaults to the initial character set), and an optional minimum,
-    maximum, and/or exact length.  The default value for ``min`` is
-    1 (a minimum value < 1 is not valid); the default values for
-    ``max`` and ``exact`` are 0, meaning no maximum or exact
-    length restriction. An optional ``excludeChars`` parameter can
-    list characters that might be found in the input ``bodyChars``
-    string; useful to define a word of all printables except for one or
-    two characters, for instance.
-
-    :class:`srange` is useful for defining custom character set strings
-    for defining ``Word`` expressions, using range notation from
-    regular expression character sets.
-
-    A common mistake is to use :class:`Word` to match a specific literal
-    string, as in ``Word("Address")``. Remember that :class:`Word`
-    uses the string argument to define *sets* of matchable characters.
-    This expression would match "Add", "AAA", "dAred", or any other word
-    made up of the characters 'A', 'd', 'r', 'e', and 's'. To match an
-    exact literal string, use :class:`Literal` or :class:`Keyword`.
-
-    pyparsing includes helper strings for building Words:
-
-     - :class:`alphas`
-     - :class:`nums`
-     - :class:`alphanums`
-     - :class:`hexnums`
-     - :class:`alphas8bit` (alphabetic characters in ASCII range 128-255
-       - accented, tilded, umlauted, etc.)
-     - :class:`punc8bit` (non-alphabetic characters in ASCII range
-       128-255 - currency, symbols, superscripts, diacriticals, etc.)
-     - :class:`printables` (any non-whitespace character)
-
-    Example::
-
-        # a word composed of digits
-        integer = Word(nums) # equivalent to Word("0123456789") or Word(srange("0-9"))
-
-        # a word with a leading capital, and zero or more lowercase
-        capital_word = Word(alphas.upper(), alphas.lower())
-
-        # hostnames are alphanumeric, with leading alpha, and '-'
-        hostname = Word(alphas, alphanums + '-')
-
-        # roman numeral (not a strict parser, accepts invalid mix of characters)
-        roman = Word("IVXLCDM")
-
-        # any string of non-whitespace characters, except for ','
-        csv_value = Word(printables, excludeChars=",")
-    """
-    def __init__(self, initChars, bodyChars=None, min=1, max=0, exact=0, asKeyword=False, excludeChars=None):
-        super(Word, self).__init__()
-        if excludeChars:
-            excludeChars = set(excludeChars)
-            initChars = ''.join(c for c in initChars if c not in excludeChars)
-            if bodyChars:
-                bodyChars = ''.join(c for c in bodyChars if c not in excludeChars)
-        self.initCharsOrig = initChars
-        self.initChars = set(initChars)
-        if bodyChars:
-            self.bodyCharsOrig = bodyChars
-            self.bodyChars = set(bodyChars)
-        else:
-            self.bodyCharsOrig = initChars
-            self.bodyChars = set(initChars)
-
-        self.maxSpecified = max > 0
-
-        if min < 1:
-            raise ValueError("cannot specify a minimum length < 1; use Optional(Word()) if zero-length word is permitted")
-
-        self.minLen = min
-
-        if max > 0:
-            self.maxLen = max
-        else:
-            self.maxLen = _MAX_INT
-
-        if exact > 0:
-            self.maxLen = exact
-            self.minLen = exact
-
-        self.name = _ustr(self)
-        self.errmsg = "Expected " + self.name
-        self.mayIndexError = False
-        self.asKeyword = asKeyword
-
-        if ' ' not in self.initCharsOrig + self.bodyCharsOrig and (min == 1 and max == 0 and exact == 0):
-            if self.bodyCharsOrig == self.initCharsOrig:
-                self.reString = "[%s]+" % _escapeRegexRangeChars(self.initCharsOrig)
-            elif len(self.initCharsOrig) == 1:
-                self.reString = "%s[%s]*" % (re.escape(self.initCharsOrig),
-                                             _escapeRegexRangeChars(self.bodyCharsOrig),)
-            else:
-                self.reString = "[%s][%s]*" % (_escapeRegexRangeChars(self.initCharsOrig),
-                                               _escapeRegexRangeChars(self.bodyCharsOrig),)
-            if self.asKeyword:
-                self.reString = r"\b" + self.reString + r"\b"
-
-            try:
-                self.re = re.compile(self.reString)
-            except Exception:
-                self.re = None
-            else:
-                self.re_match = self.re.match
-                self.__class__ = _WordRegex
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc] not in self.initChars:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        start = loc
-        loc += 1
-        instrlen = len(instring)
-        bodychars = self.bodyChars
-        maxloc = start + self.maxLen
-        maxloc = min(maxloc, instrlen)
-        while loc < maxloc and instring[loc] in bodychars:
-            loc += 1
-
-        throwException = False
-        if loc - start < self.minLen:
-            throwException = True
-        elif self.maxSpecified and loc < instrlen and instring[loc] in bodychars:
-            throwException = True
-        elif self.asKeyword:
-            if (start > 0 and instring[start - 1] in bodychars
-                    or loc < instrlen and instring[loc] in bodychars):
-                throwException = True
-
-        if throwException:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        return loc, instring[start:loc]
-
-    def __str__(self):
-        try:
-            return super(Word, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None:
-
-            def charsAsStr(s):
-                if len(s) > 4:
-                    return s[:4] + "..."
-                else:
-                    return s
-
-            if self.initCharsOrig != self.bodyCharsOrig:
-                self.strRepr = "W:(%s, %s)" % (charsAsStr(self.initCharsOrig), charsAsStr(self.bodyCharsOrig))
-            else:
-                self.strRepr = "W:(%s)" % charsAsStr(self.initCharsOrig)
-
-        return self.strRepr
-
-class _WordRegex(Word):
-    def parseImpl(self, instring, loc, doActions=True):
-        result = self.re_match(instring, loc)
-        if not result:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        loc = result.end()
-        return loc, result.group()
-
-
-class Char(_WordRegex):
-    """A short-cut class for defining ``Word(characters, exact=1)``,
-    when defining a match of any single character in a string of
-    characters.
-    """
-    def __init__(self, charset, asKeyword=False, excludeChars=None):
-        super(Char, self).__init__(charset, exact=1, asKeyword=asKeyword, excludeChars=excludeChars)
-        self.reString = "[%s]" % _escapeRegexRangeChars(''.join(self.initChars))
-        if asKeyword:
-            self.reString = r"\b%s\b" % self.reString
-        self.re = re.compile(self.reString)
-        self.re_match = self.re.match
-
-
-class Regex(Token):
-    r"""Token for matching strings that match a given regular
-    expression. Defined with string specifying the regular expression in
-    a form recognized by the stdlib Python  `re module <https://docs.python.org/3/library/re.html>`_.
-    If the given regex contains named groups (defined using ``(?P<name>...)``),
-    these will be preserved as named parse results.
-
-    If instead of the Python stdlib re module you wish to use a different RE module
-    (such as the `regex` module), you can replace it by either building your
-    Regex object with a compiled RE that was compiled using regex:
-
-    Example::
-
-        realnum = Regex(r"[+-]?\d+\.\d*")
-        date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
-        # ref: https://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression
-        roman = Regex(r"M{0,4}(CM|CD|D?{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})")
-
-        # use regex module instead of stdlib re module to construct a Regex using
-        # a compiled regular expression
-        import regex
-        parser = pp.Regex(regex.compile(r'[0-9]'))
-
-    """
-    def __init__(self, pattern, flags=0, asGroupList=False, asMatch=False):
-        """The parameters ``pattern`` and ``flags`` are passed
-        to the ``re.compile()`` function as-is. See the Python
-        `re module <https://docs.python.org/3/library/re.html>`_ module for an
-        explanation of the acceptable patterns and flags.
-        """
-        super(Regex, self).__init__()
-
-        if isinstance(pattern, basestring):
-            if not pattern:
-                warnings.warn("null string passed to Regex; use Empty() instead",
-                              SyntaxWarning, stacklevel=2)
-
-            self.pattern = pattern
-            self.flags = flags
-
-            try:
-                self.re = re.compile(self.pattern, self.flags)
-                self.reString = self.pattern
-            except sre_constants.error:
-                warnings.warn("invalid pattern (%s) passed to Regex" % pattern,
-                              SyntaxWarning, stacklevel=2)
-                raise
-
-        elif hasattr(pattern, 'pattern') and hasattr(pattern, 'match'):
-            self.re = pattern
-            self.pattern = self.reString = pattern.pattern
-            self.flags = flags
-
-        else:
-            raise TypeError("Regex may only be constructed with a string or a compiled RE object")
-
-        self.re_match = self.re.match
-
-        self.name = _ustr(self)
-        self.errmsg = "Expected " + self.name
-        self.mayIndexError = False
-        self.mayReturnEmpty = self.re_match("") is not None
-        self.asGroupList = asGroupList
-        self.asMatch = asMatch
-        if self.asGroupList:
-            self.parseImpl = self.parseImplAsGroupList
-        if self.asMatch:
-            self.parseImpl = self.parseImplAsMatch
-
-    def parseImpl(self, instring, loc, doActions=True):
-        result = self.re_match(instring, loc)
-        if not result:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        loc = result.end()
-        ret = ParseResults(result.group())
-        d = result.groupdict()
-        if d:
-            for k, v in d.items():
-                ret[k] = v
-        return loc, ret
-
-    def parseImplAsGroupList(self, instring, loc, doActions=True):
-        result = self.re_match(instring, loc)
-        if not result:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        loc = result.end()
-        ret = result.groups()
-        return loc, ret
-
-    def parseImplAsMatch(self, instring, loc, doActions=True):
-        result = self.re_match(instring, loc)
-        if not result:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        loc = result.end()
-        ret = result
-        return loc, ret
-
-    def __str__(self):
-        try:
-            return super(Regex, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None:
-            self.strRepr = "Re:(%s)" % repr(self.pattern)
-
-        return self.strRepr
-
-    def sub(self, repl):
-        r"""
-        Return Regex with an attached parse action to transform the parsed
-        result as if called using `re.sub(expr, repl, string) <https://docs.python.org/3/library/re.html#re.sub>`_.
-
-        Example::
-
-            make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
-            print(make_html.transformString("h1:main title:"))
-            # prints "<h1>main title</h1>"
-        """
-        if self.asGroupList:
-            warnings.warn("cannot use sub() with Regex(asGroupList=True)",
-                          SyntaxWarning, stacklevel=2)
-            raise SyntaxError()
-
-        if self.asMatch and callable(repl):
-            warnings.warn("cannot use sub() with a callable with Regex(asMatch=True)",
-                          SyntaxWarning, stacklevel=2)
-            raise SyntaxError()
-
-        if self.asMatch:
-            def pa(tokens):
-                return tokens[0].expand(repl)
-        else:
-            def pa(tokens):
-                return self.re.sub(repl, tokens[0])
-        return self.addParseAction(pa)
-
-class QuotedString(Token):
-    r"""
-    Token for matching strings that are delimited by quoting characters.
-
-    Defined with the following parameters:
-
-        - quoteChar - string of one or more characters defining the
-          quote delimiting string
-        - escChar - character to escape quotes, typically backslash
-          (default= ``None``)
-        - escQuote - special quote sequence to escape an embedded quote
-          string (such as SQL's ``""`` to escape an embedded ``"``)
-          (default= ``None``)
-        - multiline - boolean indicating whether quotes can span
-          multiple lines (default= ``False``)
-        - unquoteResults - boolean indicating whether the matched text
-          should be unquoted (default= ``True``)
-        - endQuoteChar - string of one or more characters defining the
-          end of the quote delimited string (default= ``None``  => same as
-          quoteChar)
-        - convertWhitespaceEscapes - convert escaped whitespace
-          (``'\t'``, ``'\n'``, etc.) to actual whitespace
-          (default= ``True``)
-
-    Example::
-
-        qs = QuotedString('"')
-        print(qs.searchString('lsjdf "This is the quote" sldjf'))
-        complex_qs = QuotedString('{{', endQuoteChar='}}')
-        print(complex_qs.searchString('lsjdf {{This is the "quote"}} sldjf'))
-        sql_qs = QuotedString('"', escQuote='""')
-        print(sql_qs.searchString('lsjdf "This is the quote with ""embedded"" quotes" sldjf'))
-
-    prints::
-
-        [['This is the quote']]
-        [['This is the "quote"']]
-        [['This is the quote with "embedded" quotes']]
-    """
-    def __init__(self, quoteChar, escChar=None, escQuote=None, multiline=False,
-                 unquoteResults=True, endQuoteChar=None, convertWhitespaceEscapes=True):
-        super(QuotedString, self).__init__()
-
-        # remove white space from quote chars - wont work anyway
-        quoteChar = quoteChar.strip()
-        if not quoteChar:
-            warnings.warn("quoteChar cannot be the empty string", SyntaxWarning, stacklevel=2)
-            raise SyntaxError()
-
-        if endQuoteChar is None:
-            endQuoteChar = quoteChar
-        else:
-            endQuoteChar = endQuoteChar.strip()
-            if not endQuoteChar:
-                warnings.warn("endQuoteChar cannot be the empty string", SyntaxWarning, stacklevel=2)
-                raise SyntaxError()
-
-        self.quoteChar = quoteChar
-        self.quoteCharLen = len(quoteChar)
-        self.firstQuoteChar = quoteChar[0]
-        self.endQuoteChar = endQuoteChar
-        self.endQuoteCharLen = len(endQuoteChar)
-        self.escChar = escChar
-        self.escQuote = escQuote
-        self.unquoteResults = unquoteResults
-        self.convertWhitespaceEscapes = convertWhitespaceEscapes
-
-        if multiline:
-            self.flags = re.MULTILINE | re.DOTALL
-            self.pattern = r'%s(?:[^%s%s]' % (re.escape(self.quoteChar),
-                                              _escapeRegexRangeChars(self.endQuoteChar[0]),
-                                              (escChar is not None and _escapeRegexRangeChars(escChar) or ''))
-        else:
-            self.flags = 0
-            self.pattern = r'%s(?:[^%s\n\r%s]' % (re.escape(self.quoteChar),
-                                                  _escapeRegexRangeChars(self.endQuoteChar[0]),
-                                                  (escChar is not None and _escapeRegexRangeChars(escChar) or ''))
-        if len(self.endQuoteChar) > 1:
-            self.pattern += (
-                '|(?:' + ')|(?:'.join("%s[^%s]" % (re.escape(self.endQuoteChar[:i]),
-                                                   _escapeRegexRangeChars(self.endQuoteChar[i]))
-                                      for i in range(len(self.endQuoteChar) - 1, 0, -1)) + ')')
-
-        if escQuote:
-            self.pattern += (r'|(?:%s)' % re.escape(escQuote))
-        if escChar:
-            self.pattern += (r'|(?:%s.)' % re.escape(escChar))
-            self.escCharReplacePattern = re.escape(self.escChar) + "(.)"
-        self.pattern += (r')*%s' % re.escape(self.endQuoteChar))
-
-        try:
-            self.re = re.compile(self.pattern, self.flags)
-            self.reString = self.pattern
-            self.re_match = self.re.match
-        except sre_constants.error:
-            warnings.warn("invalid pattern (%s) passed to Regex" % self.pattern,
-                          SyntaxWarning, stacklevel=2)
-            raise
-
-        self.name = _ustr(self)
-        self.errmsg = "Expected " + self.name
-        self.mayIndexError = False
-        self.mayReturnEmpty = True
-
-    def parseImpl(self, instring, loc, doActions=True):
-        result = instring[loc] == self.firstQuoteChar and self.re_match(instring, loc) or None
-        if not result:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        loc = result.end()
-        ret = result.group()
-
-        if self.unquoteResults:
-
-            # strip off quotes
-            ret = ret[self.quoteCharLen: -self.endQuoteCharLen]
-
-            if isinstance(ret, basestring):
-                # replace escaped whitespace
-                if '\\' in ret and self.convertWhitespaceEscapes:
-                    ws_map = {
-                        r'\t': '\t',
-                        r'\n': '\n',
-                        r'\f': '\f',
-                        r'\r': '\r',
-                    }
-                    for wslit, wschar in ws_map.items():
-                        ret = ret.replace(wslit, wschar)
-
-                # replace escaped characters
-                if self.escChar:
-                    ret = re.sub(self.escCharReplacePattern, r"\g<1>", ret)
-
-                # replace escaped quotes
-                if self.escQuote:
-                    ret = ret.replace(self.escQuote, self.endQuoteChar)
-
-        return loc, ret
-
-    def __str__(self):
-        try:
-            return super(QuotedString, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None:
-            self.strRepr = "quoted string, starting with %s ending with %s" % (self.quoteChar, self.endQuoteChar)
-
-        return self.strRepr
-
-
-class CharsNotIn(Token):
-    """Token for matching words composed of characters *not* in a given
-    set (will include whitespace in matched characters if not listed in
-    the provided exclusion set - see example). Defined with string
-    containing all disallowed characters, and an optional minimum,
-    maximum, and/or exact length.  The default value for ``min`` is
-    1 (a minimum value < 1 is not valid); the default values for
-    ``max`` and ``exact`` are 0, meaning no maximum or exact
-    length restriction.
-
-    Example::
-
-        # define a comma-separated-value as anything that is not a ','
-        csv_value = CharsNotIn(',')
-        print(delimitedList(csv_value).parseString("dkls,lsdkjf,s12 34,@!#,213"))
-
-    prints::
-
-        ['dkls', 'lsdkjf', 's12 34', '@!#', '213']
-    """
-    def __init__(self, notChars, min=1, max=0, exact=0):
-        super(CharsNotIn, self).__init__()
-        self.skipWhitespace = False
-        self.notChars = notChars
-
-        if min < 1:
-            raise ValueError("cannot specify a minimum length < 1; use "
-                             "Optional(CharsNotIn()) if zero-length char group is permitted")
-
-        self.minLen = min
-
-        if max > 0:
-            self.maxLen = max
-        else:
-            self.maxLen = _MAX_INT
-
-        if exact > 0:
-            self.maxLen = exact
-            self.minLen = exact
-
-        self.name = _ustr(self)
-        self.errmsg = "Expected " + self.name
-        self.mayReturnEmpty = (self.minLen == 0)
-        self.mayIndexError = False
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc] in self.notChars:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        start = loc
-        loc += 1
-        notchars = self.notChars
-        maxlen = min(start + self.maxLen, len(instring))
-        while loc < maxlen and instring[loc] not in notchars:
-            loc += 1
-
-        if loc - start < self.minLen:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        return loc, instring[start:loc]
-
-    def __str__(self):
-        try:
-            return super(CharsNotIn, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None:
-            if len(self.notChars) > 4:
-                self.strRepr = "!W:(%s...)" % self.notChars[:4]
-            else:
-                self.strRepr = "!W:(%s)" % self.notChars
-
-        return self.strRepr
-
-class White(Token):
-    """Special matching class for matching whitespace.  Normally,
-    whitespace is ignored by pyparsing grammars.  This class is included
-    when some whitespace structures are significant.  Define with
-    a string containing the whitespace characters to be matched; default
-    is ``" \\t\\r\\n"``.  Also takes optional ``min``,
-    ``max``, and ``exact`` arguments, as defined for the
-    :class:`Word` class.
-    """
-    whiteStrs = {
-        ' ' : '<SP>',
-        '\t': '<TAB>',
-        '\n': '<LF>',
-        '\r': '<CR>',
-        '\f': '<FF>',
-        u'\u00A0': '<NBSP>',
-        u'\u1680': '<OGHAM_SPACE_MARK>',
-        u'\u180E': '<MONGOLIAN_VOWEL_SEPARATOR>',
-        u'\u2000': '<EN_QUAD>',
-        u'\u2001': '<EM_QUAD>',
-        u'\u2002': '<EN_SPACE>',
-        u'\u2003': '<EM_SPACE>',
-        u'\u2004': '<THREE-PER-EM_SPACE>',
-        u'\u2005': '<FOUR-PER-EM_SPACE>',
-        u'\u2006': '<SIX-PER-EM_SPACE>',
-        u'\u2007': '<FIGURE_SPACE>',
-        u'\u2008': '<PUNCTUATION_SPACE>',
-        u'\u2009': '<THIN_SPACE>',
-        u'\u200A': '<HAIR_SPACE>',
-        u'\u200B': '<ZERO_WIDTH_SPACE>',
-        u'\u202F': '<NNBSP>',
-        u'\u205F': '<MMSP>',
-        u'\u3000': '<IDEOGRAPHIC_SPACE>',
-        }
-    def __init__(self, ws=" \t\r\n", min=1, max=0, exact=0):
-        super(White, self).__init__()
-        self.matchWhite = ws
-        self.setWhitespaceChars("".join(c for c in self.whiteChars if c not in self.matchWhite))
-        # ~ self.leaveWhitespace()
-        self.name = ("".join(White.whiteStrs[c] for c in self.matchWhite))
-        self.mayReturnEmpty = True
-        self.errmsg = "Expected " + self.name
-
-        self.minLen = min
-
-        if max > 0:
-            self.maxLen = max
-        else:
-            self.maxLen = _MAX_INT
-
-        if exact > 0:
-            self.maxLen = exact
-            self.minLen = exact
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if instring[loc] not in self.matchWhite:
-            raise ParseException(instring, loc, self.errmsg, self)
-        start = loc
-        loc += 1
-        maxloc = start + self.maxLen
-        maxloc = min(maxloc, len(instring))
-        while loc < maxloc and instring[loc] in self.matchWhite:
-            loc += 1
-
-        if loc - start < self.minLen:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        return loc, instring[start:loc]
-
-
-class _PositionToken(Token):
-    def __init__(self):
-        super(_PositionToken, self).__init__()
-        self.name = self.__class__.__name__
-        self.mayReturnEmpty = True
-        self.mayIndexError = False
-
-class GoToColumn(_PositionToken):
-    """Token to advance to a specific column of input text; useful for
-    tabular report scraping.
-    """
-    def __init__(self, colno):
-        super(GoToColumn, self).__init__()
-        self.col = colno
-
-    def preParse(self, instring, loc):
-        if col(loc, instring) != self.col:
-            instrlen = len(instring)
-            if self.ignoreExprs:
-                loc = self._skipIgnorables(instring, loc)
-            while loc < instrlen and instring[loc].isspace() and col(loc, instring) != self.col:
-                loc += 1
-        return loc
-
-    def parseImpl(self, instring, loc, doActions=True):
-        thiscol = col(loc, instring)
-        if thiscol > self.col:
-            raise ParseException(instring, loc, "Text not in expected column", self)
-        newloc = loc + self.col - thiscol
-        ret = instring[loc: newloc]
-        return newloc, ret
-
-
-class LineStart(_PositionToken):
-    r"""Matches if current position is at the beginning of a line within
-    the parse string
-
-    Example::
-
-        test = '''\
-        AAA this line
-        AAA and this line
-          AAA but not this one
-        B AAA and definitely not this one
-        '''
-
-        for t in (LineStart() + 'AAA' + restOfLine).searchString(test):
-            print(t)
-
-    prints::
-
-        ['AAA', ' this line']
-        ['AAA', ' and this line']
-
-    """
-    def __init__(self):
-        super(LineStart, self).__init__()
-        self.errmsg = "Expected start of line"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if col(loc, instring) == 1:
-            return loc, []
-        raise ParseException(instring, loc, self.errmsg, self)
-
-class LineEnd(_PositionToken):
-    """Matches if current position is at the end of a line within the
-    parse string
-    """
-    def __init__(self):
-        super(LineEnd, self).__init__()
-        self.setWhitespaceChars(ParserElement.DEFAULT_WHITE_CHARS.replace("\n", ""))
-        self.errmsg = "Expected end of line"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if loc < len(instring):
-            if instring[loc] == "\n":
-                return loc + 1, "\n"
-            else:
-                raise ParseException(instring, loc, self.errmsg, self)
-        elif loc == len(instring):
-            return loc + 1, []
-        else:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-class StringStart(_PositionToken):
-    """Matches if current position is at the beginning of the parse
-    string
-    """
-    def __init__(self):
-        super(StringStart, self).__init__()
-        self.errmsg = "Expected start of text"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if loc != 0:
-            # see if entire string up to here is just whitespace and ignoreables
-            if loc != self.preParse(instring, 0):
-                raise ParseException(instring, loc, self.errmsg, self)
-        return loc, []
-
-class StringEnd(_PositionToken):
-    """Matches if current position is at the end of the parse string
-    """
-    def __init__(self):
-        super(StringEnd, self).__init__()
-        self.errmsg = "Expected end of text"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if loc < len(instring):
-            raise ParseException(instring, loc, self.errmsg, self)
-        elif loc == len(instring):
-            return loc + 1, []
-        elif loc > len(instring):
-            return loc, []
-        else:
-            raise ParseException(instring, loc, self.errmsg, self)
-
-class WordStart(_PositionToken):
-    """Matches if the current position is at the beginning of a Word,
-    and is not preceded by any character in a given set of
-    ``wordChars`` (default= ``printables``). To emulate the
-    ``\b`` behavior of regular expressions, use
-    ``WordStart(alphanums)``. ``WordStart`` will also match at
-    the beginning of the string being parsed, or at the beginning of
-    a line.
-    """
-    def __init__(self, wordChars=printables):
-        super(WordStart, self).__init__()
-        self.wordChars = set(wordChars)
-        self.errmsg = "Not at the start of a word"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if loc != 0:
-            if (instring[loc - 1] in self.wordChars
-                    or instring[loc] not in self.wordChars):
-                raise ParseException(instring, loc, self.errmsg, self)
-        return loc, []
-
-class WordEnd(_PositionToken):
-    """Matches if the current position is at the end of a Word, and is
-    not followed by any character in a given set of ``wordChars``
-    (default= ``printables``). To emulate the ``\b`` behavior of
-    regular expressions, use ``WordEnd(alphanums)``. ``WordEnd``
-    will also match at the end of the string being parsed, or at the end
-    of a line.
-    """
-    def __init__(self, wordChars=printables):
-        super(WordEnd, self).__init__()
-        self.wordChars = set(wordChars)
-        self.skipWhitespace = False
-        self.errmsg = "Not at the end of a word"
-
-    def parseImpl(self, instring, loc, doActions=True):
-        instrlen = len(instring)
-        if instrlen > 0 and loc < instrlen:
-            if (instring[loc] in self.wordChars or
-                    instring[loc - 1] not in self.wordChars):
-                raise ParseException(instring, loc, self.errmsg, self)
-        return loc, []
-
-
-class ParseExpression(ParserElement):
-    """Abstract subclass of ParserElement, for combining and
-    post-processing parsed tokens.
-    """
-    def __init__(self, exprs, savelist=False):
-        super(ParseExpression, self).__init__(savelist)
-        if isinstance(exprs, _generatorType):
-            exprs = list(exprs)
-
-        if isinstance(exprs, basestring):
-            self.exprs = [self._literalStringClass(exprs)]
-        elif isinstance(exprs, ParserElement):
-            self.exprs = [exprs]
-        elif isinstance(exprs, Iterable):
-            exprs = list(exprs)
-            # if sequence of strings provided, wrap with Literal
-            if any(isinstance(expr, basestring) for expr in exprs):
-                exprs = (self._literalStringClass(e) if isinstance(e, basestring) else e for e in exprs)
-            self.exprs = list(exprs)
-        else:
-            try:
-                self.exprs = list(exprs)
-            except TypeError:
-                self.exprs = [exprs]
-        self.callPreparse = False
-
-    def append(self, other):
-        self.exprs.append(other)
-        self.strRepr = None
-        return self
-
-    def leaveWhitespace(self):
-        """Extends ``leaveWhitespace`` defined in base class, and also invokes ``leaveWhitespace`` on
-           all contained expressions."""
-        self.skipWhitespace = False
-        self.exprs = [e.copy() for e in self.exprs]
-        for e in self.exprs:
-            e.leaveWhitespace()
-        return self
-
-    def ignore(self, other):
-        if isinstance(other, Suppress):
-            if other not in self.ignoreExprs:
-                super(ParseExpression, self).ignore(other)
-                for e in self.exprs:
-                    e.ignore(self.ignoreExprs[-1])
-        else:
-            super(ParseExpression, self).ignore(other)
-            for e in self.exprs:
-                e.ignore(self.ignoreExprs[-1])
-        return self
-
-    def __str__(self):
-        try:
-            return super(ParseExpression, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None:
-            self.strRepr = "%s:(%s)" % (self.__class__.__name__, _ustr(self.exprs))
-        return self.strRepr
-
-    def streamline(self):
-        super(ParseExpression, self).streamline()
-
-        for e in self.exprs:
-            e.streamline()
-
-        # collapse nested And's of the form And(And(And(a, b), c), d) to And(a, b, c, d)
-        # but only if there are no parse actions or resultsNames on the nested And's
-        # (likewise for Or's and MatchFirst's)
-        if len(self.exprs) == 2:
-            other = self.exprs[0]
-            if (isinstance(other, self.__class__)
-                    and not other.parseAction
-                    and other.resultsName is None
-                    and not other.debug):
-                self.exprs = other.exprs[:] + [self.exprs[1]]
-                self.strRepr = None
-                self.mayReturnEmpty |= other.mayReturnEmpty
-                self.mayIndexError  |= other.mayIndexError
-
-            other = self.exprs[-1]
-            if (isinstance(other, self.__class__)
-                    and not other.parseAction
-                    and other.resultsName is None
-                    and not other.debug):
-                self.exprs = self.exprs[:-1] + other.exprs[:]
-                self.strRepr = None
-                self.mayReturnEmpty |= other.mayReturnEmpty
-                self.mayIndexError  |= other.mayIndexError
-
-        self.errmsg = "Expected " + _ustr(self)
-
-        return self
-
-    def validate(self, validateTrace=None):
-        tmp = (validateTrace if validateTrace is not None else [])[:] + [self]
-        for e in self.exprs:
-            e.validate(tmp)
-        self.checkRecursion([])
-
-    def copy(self):
-        ret = super(ParseExpression, self).copy()
-        ret.exprs = [e.copy() for e in self.exprs]
-        return ret
-
-    def _setResultsName(self, name, listAllMatches=False):
-        if __diag__.warn_ungrouped_named_tokens_in_collection:
-            for e in self.exprs:
-                if isinstance(e, ParserElement) and e.resultsName:
-                    warnings.warn("{0}: setting results name {1!r} on {2} expression "
-                                  "collides with {3!r} on contained expression".format("warn_ungrouped_named_tokens_in_collection",
-                                                                                       name,
-                                                                                       type(self).__name__,
-                                                                                       e.resultsName),
-                                  stacklevel=3)
-
-        return super(ParseExpression, self)._setResultsName(name, listAllMatches)
-
-
-class And(ParseExpression):
-    """
-    Requires all given :class:`ParseExpression` s to be found in the given order.
-    Expressions may be separated by whitespace.
-    May be constructed using the ``'+'`` operator.
-    May also be constructed using the ``'-'`` operator, which will
-    suppress backtracking.
-
-    Example::
-
-        integer = Word(nums)
-        name_expr = OneOrMore(Word(alphas))
-
-        expr = And([integer("id"), name_expr("name"), integer("age")])
-        # more easily written as:
-        expr = integer("id") + name_expr("name") + integer("age")
-    """
-
-    class _ErrorStop(Empty):
-        def __init__(self, *args, **kwargs):
-            super(And._ErrorStop, self).__init__(*args, **kwargs)
-            self.name = '-'
-            self.leaveWhitespace()
-
-    def __init__(self, exprs, savelist=True):
-        exprs = list(exprs)
-        if exprs and Ellipsis in exprs:
-            tmp = []
-            for i, expr in enumerate(exprs):
-                if expr is Ellipsis:
-                    if i < len(exprs) - 1:
-                        skipto_arg = (Empty() + exprs[i + 1]).exprs[-1]
-                        tmp.append(SkipTo(skipto_arg)("_skipped*"))
-                    else:
-                        raise Exception("cannot construct And with sequence ending in ...")
-                else:
-                    tmp.append(expr)
-            exprs[:] = tmp
-        super(And, self).__init__(exprs, savelist)
-        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
-        self.setWhitespaceChars(self.exprs[0].whiteChars)
-        self.skipWhitespace = self.exprs[0].skipWhitespace
-        self.callPreparse = True
-
-    def streamline(self):
-        # collapse any _PendingSkip's
-        if self.exprs:
-            if any(isinstance(e, ParseExpression) and e.exprs and isinstance(e.exprs[-1], _PendingSkip)
-                   for e in self.exprs[:-1]):
-                for i, e in enumerate(self.exprs[:-1]):
-                    if e is None:
-                        continue
-                    if (isinstance(e, ParseExpression)
-                            and e.exprs and isinstance(e.exprs[-1], _PendingSkip)):
-                        e.exprs[-1] = e.exprs[-1] + self.exprs[i + 1]
-                        self.exprs[i + 1] = None
-                self.exprs = [e for e in self.exprs if e is not None]
-
-        super(And, self).streamline()
-        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
-        return self
-
-    def parseImpl(self, instring, loc, doActions=True):
-        # pass False as last arg to _parse for first element, since we already
-        # pre-parsed the string as part of our And pre-parsing
-        loc, resultlist = self.exprs[0]._parse(instring, loc, doActions, callPreParse=False)
-        errorStop = False
-        for e in self.exprs[1:]:
-            if isinstance(e, And._ErrorStop):
-                errorStop = True
-                continue
-            if errorStop:
-                try:
-                    loc, exprtokens = e._parse(instring, loc, doActions)
-                except ParseSyntaxException:
-                    raise
-                except ParseBaseException as pe:
-                    pe.__traceback__ = None
-                    raise ParseSyntaxException._from_exception(pe)
-                except IndexError:
-                    raise ParseSyntaxException(instring, len(instring), self.errmsg, self)
-            else:
-                loc, exprtokens = e._parse(instring, loc, doActions)
-            if exprtokens or exprtokens.haskeys():
-                resultlist += exprtokens
-        return loc, resultlist
-
-    def __iadd__(self, other):
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        return self.append(other)  # And([self, other])
-
-    def checkRecursion(self, parseElementList):
-        subRecCheckList = parseElementList[:] + [self]
-        for e in self.exprs:
-            e.checkRecursion(subRecCheckList)
-            if not e.mayReturnEmpty:
-                break
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "{" + " ".join(_ustr(e) for e in self.exprs) + "}"
-
-        return self.strRepr
-
-
-class Or(ParseExpression):
-    """Requires that at least one :class:`ParseExpression` is found. If
-    two expressions match, the expression that matches the longest
-    string will be used. May be constructed using the ``'^'``
-    operator.
-
-    Example::
-
-        # construct Or using '^' operator
-
-        number = Word(nums) ^ Combine(Word(nums) + '.' + Word(nums))
-        print(number.searchString("123 3.1416 789"))
-
-    prints::
-
-        [['123'], ['3.1416'], ['789']]
-    """
-    def __init__(self, exprs, savelist=False):
-        super(Or, self).__init__(exprs, savelist)
-        if self.exprs:
-            self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
-        else:
-            self.mayReturnEmpty = True
-
-    def streamline(self):
-        super(Or, self).streamline()
-        if __compat__.collect_all_And_tokens:
-            self.saveAsList = any(e.saveAsList for e in self.exprs)
-        return self
-
-    def parseImpl(self, instring, loc, doActions=True):
-        maxExcLoc = -1
-        maxException = None
-        matches = []
-        for e in self.exprs:
-            try:
-                loc2 = e.tryParse(instring, loc)
-            except ParseException as err:
-                err.__traceback__ = None
-                if err.loc > maxExcLoc:
-                    maxException = err
-                    maxExcLoc = err.loc
-            except IndexError:
-                if len(instring) > maxExcLoc:
-                    maxException = ParseException(instring, len(instring), e.errmsg, self)
-                    maxExcLoc = len(instring)
-            else:
-                # save match among all matches, to retry longest to shortest
-                matches.append((loc2, e))
-
-        if matches:
-            # re-evaluate all matches in descending order of length of match, in case attached actions
-            # might change whether or how much they match of the input.
-            matches.sort(key=itemgetter(0), reverse=True)
-
-            if not doActions:
-                # no further conditions or parse actions to change the selection of
-                # alternative, so the first match will be the best match
-                best_expr = matches[0][1]
-                return best_expr._parse(instring, loc, doActions)
-
-            longest = -1, None
-            for loc1, expr1 in matches:
-                if loc1 <= longest[0]:
-                    # already have a longer match than this one will deliver, we are done
-                    return longest
-
-                try:
-                    loc2, toks = expr1._parse(instring, loc, doActions)
-                except ParseException as err:
-                    err.__traceback__ = None
-                    if err.loc > maxExcLoc:
-                        maxException = err
-                        maxExcLoc = err.loc
-                else:
-                    if loc2 >= loc1:
-                        return loc2, toks
-                    # didn't match as much as before
-                    elif loc2 > longest[0]:
-                        longest = loc2, toks
-
-            if longest != (-1, None):
-                return longest
-
-        if maxException is not None:
-            maxException.msg = self.errmsg
-            raise maxException
-        else:
-            raise ParseException(instring, loc, "no defined alternatives to match", self)
-
-
-    def __ixor__(self, other):
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        return self.append(other)  # Or([self, other])
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "{" + " ^ ".join(_ustr(e) for e in self.exprs) + "}"
-
-        return self.strRepr
-
-    def checkRecursion(self, parseElementList):
-        subRecCheckList = parseElementList[:] + [self]
-        for e in self.exprs:
-            e.checkRecursion(subRecCheckList)
-
-    def _setResultsName(self, name, listAllMatches=False):
-        if (not __compat__.collect_all_And_tokens
-                and __diag__.warn_multiple_tokens_in_named_alternation):
-            if any(isinstance(e, And) for e in self.exprs):
-                warnings.warn("{0}: setting results name {1!r} on {2} expression "
-                              "may only return a single token for an And alternative, "
-                              "in future will return the full list of tokens".format(
-                    "warn_multiple_tokens_in_named_alternation", name, type(self).__name__),
-                    stacklevel=3)
-
-        return super(Or, self)._setResultsName(name, listAllMatches)
-
-
-class MatchFirst(ParseExpression):
-    """Requires that at least one :class:`ParseExpression` is found. If
-    two expressions match, the first one listed is the one that will
-    match. May be constructed using the ``'|'`` operator.
-
-    Example::
-
-        # construct MatchFirst using '|' operator
-
-        # watch the order of expressions to match
-        number = Word(nums) | Combine(Word(nums) + '.' + Word(nums))
-        print(number.searchString("123 3.1416 789")) #  Fail! -> [['123'], ['3'], ['1416'], ['789']]
-
-        # put more selective expression first
-        number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums)
-        print(number.searchString("123 3.1416 789")) #  Better -> [['123'], ['3.1416'], ['789']]
-    """
-    def __init__(self, exprs, savelist=False):
-        super(MatchFirst, self).__init__(exprs, savelist)
-        if self.exprs:
-            self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
-        else:
-            self.mayReturnEmpty = True
-
-    def streamline(self):
-        super(MatchFirst, self).streamline()
-        if __compat__.collect_all_And_tokens:
-            self.saveAsList = any(e.saveAsList for e in self.exprs)
-        return self
-
-    def parseImpl(self, instring, loc, doActions=True):
-        maxExcLoc = -1
-        maxException = None
-        for e in self.exprs:
-            try:
-                ret = e._parse(instring, loc, doActions)
-                return ret
-            except ParseException as err:
-                if err.loc > maxExcLoc:
-                    maxException = err
-                    maxExcLoc = err.loc
-            except IndexError:
-                if len(instring) > maxExcLoc:
-                    maxException = ParseException(instring, len(instring), e.errmsg, self)
-                    maxExcLoc = len(instring)
-
-        # only got here if no expression matched, raise exception for match that made it the furthest
-        else:
-            if maxException is not None:
-                maxException.msg = self.errmsg
-                raise maxException
-            else:
-                raise ParseException(instring, loc, "no defined alternatives to match", self)
-
-    def __ior__(self, other):
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        return self.append(other)  # MatchFirst([self, other])
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "{" + " | ".join(_ustr(e) for e in self.exprs) + "}"
-
-        return self.strRepr
-
-    def checkRecursion(self, parseElementList):
-        subRecCheckList = parseElementList[:] + [self]
-        for e in self.exprs:
-            e.checkRecursion(subRecCheckList)
-
-    def _setResultsName(self, name, listAllMatches=False):
-        if (not __compat__.collect_all_And_tokens
-                and __diag__.warn_multiple_tokens_in_named_alternation):
-            if any(isinstance(e, And) for e in self.exprs):
-                warnings.warn("{0}: setting results name {1!r} on {2} expression "
-                              "may only return a single token for an And alternative, "
-                              "in future will return the full list of tokens".format(
-                    "warn_multiple_tokens_in_named_alternation", name, type(self).__name__),
-                    stacklevel=3)
-
-        return super(MatchFirst, self)._setResultsName(name, listAllMatches)
-
-
-class Each(ParseExpression):
-    """Requires all given :class:`ParseExpression` s to be found, but in
-    any order. Expressions may be separated by whitespace.
-
-    May be constructed using the ``'&'`` operator.
-
-    Example::
-
-        color = oneOf("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN")
-        shape_type = oneOf("SQUARE CIRCLE TRIANGLE STAR HEXAGON OCTAGON")
-        integer = Word(nums)
-        shape_attr = "shape:" + shape_type("shape")
-        posn_attr = "posn:" + Group(integer("x") + ',' + integer("y"))("posn")
-        color_attr = "color:" + color("color")
-        size_attr = "size:" + integer("size")
-
-        # use Each (using operator '&') to accept attributes in any order
-        # (shape and posn are required, color and size are optional)
-        shape_spec = shape_attr & posn_attr & Optional(color_attr) & Optional(size_attr)
-
-        shape_spec.runTests('''
-            shape: SQUARE color: BLACK posn: 100, 120
-            shape: CIRCLE size: 50 color: BLUE posn: 50,80
-            color:GREEN size:20 shape:TRIANGLE posn:20,40
-            '''
-            )
-
-    prints::
-
-        shape: SQUARE color: BLACK posn: 100, 120
-        ['shape:', 'SQUARE', 'color:', 'BLACK', 'posn:', ['100', ',', '120']]
-        - color: BLACK
-        - posn: ['100', ',', '120']
-          - x: 100
-          - y: 120
-        - shape: SQUARE
-
-
-        shape: CIRCLE size: 50 color: BLUE posn: 50,80
-        ['shape:', 'CIRCLE', 'size:', '50', 'color:', 'BLUE', 'posn:', ['50', ',', '80']]
-        - color: BLUE
-        - posn: ['50', ',', '80']
-          - x: 50
-          - y: 80
-        - shape: CIRCLE
-        - size: 50
-
-
-        color: GREEN size: 20 shape: TRIANGLE posn: 20,40
-        ['color:', 'GREEN', 'size:', '20', 'shape:', 'TRIANGLE', 'posn:', ['20', ',', '40']]
-        - color: GREEN
-        - posn: ['20', ',', '40']
-          - x: 20
-          - y: 40
-        - shape: TRIANGLE
-        - size: 20
-    """
-    def __init__(self, exprs, savelist=True):
-        super(Each, self).__init__(exprs, savelist)
-        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
-        self.skipWhitespace = True
-        self.initExprGroups = True
-        self.saveAsList = True
-
-    def streamline(self):
-        super(Each, self).streamline()
-        self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
-        return self
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if self.initExprGroups:
-            self.opt1map = dict((id(e.expr), e) for e in self.exprs if isinstance(e, Optional))
-            opt1 = [e.expr for e in self.exprs if isinstance(e, Optional)]
-            opt2 = [e for e in self.exprs if e.mayReturnEmpty and not isinstance(e, (Optional, Regex))]
-            self.optionals = opt1 + opt2
-            self.multioptionals = [e.expr for e in self.exprs if isinstance(e, ZeroOrMore)]
-            self.multirequired = [e.expr for e in self.exprs if isinstance(e, OneOrMore)]
-            self.required = [e for e in self.exprs if not isinstance(e, (Optional, ZeroOrMore, OneOrMore))]
-            self.required += self.multirequired
-            self.initExprGroups = False
-        tmpLoc = loc
-        tmpReqd = self.required[:]
-        tmpOpt  = self.optionals[:]
-        matchOrder = []
-
-        keepMatching = True
-        while keepMatching:
-            tmpExprs = tmpReqd + tmpOpt + self.multioptionals + self.multirequired
-            failed = []
-            for e in tmpExprs:
-                try:
-                    tmpLoc = e.tryParse(instring, tmpLoc)
-                except ParseException:
-                    failed.append(e)
-                else:
-                    matchOrder.append(self.opt1map.get(id(e), e))
-                    if e in tmpReqd:
-                        tmpReqd.remove(e)
-                    elif e in tmpOpt:
-                        tmpOpt.remove(e)
-            if len(failed) == len(tmpExprs):
-                keepMatching = False
-
-        if tmpReqd:
-            missing = ", ".join(_ustr(e) for e in tmpReqd)
-            raise ParseException(instring, loc, "Missing one or more required elements (%s)" % missing)
-
-        # add any unmatched Optionals, in case they have default values defined
-        matchOrder += [e for e in self.exprs if isinstance(e, Optional) and e.expr in tmpOpt]
-
-        resultlist = []
-        for e in matchOrder:
-            loc, results = e._parse(instring, loc, doActions)
-            resultlist.append(results)
-
-        finalResults = sum(resultlist, ParseResults([]))
-        return loc, finalResults
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "{" + " & ".join(_ustr(e) for e in self.exprs) + "}"
-
-        return self.strRepr
-
-    def checkRecursion(self, parseElementList):
-        subRecCheckList = parseElementList[:] + [self]
-        for e in self.exprs:
-            e.checkRecursion(subRecCheckList)
-
-
-class ParseElementEnhance(ParserElement):
-    """Abstract subclass of :class:`ParserElement`, for combining and
-    post-processing parsed tokens.
-    """
-    def __init__(self, expr, savelist=False):
-        super(ParseElementEnhance, self).__init__(savelist)
-        if isinstance(expr, basestring):
-            if issubclass(self._literalStringClass, Token):
-                expr = self._literalStringClass(expr)
-            else:
-                expr = self._literalStringClass(Literal(expr))
-        self.expr = expr
-        self.strRepr = None
-        if expr is not None:
-            self.mayIndexError = expr.mayIndexError
-            self.mayReturnEmpty = expr.mayReturnEmpty
-            self.setWhitespaceChars(expr.whiteChars)
-            self.skipWhitespace = expr.skipWhitespace
-            self.saveAsList = expr.saveAsList
-            self.callPreparse = expr.callPreparse
-            self.ignoreExprs.extend(expr.ignoreExprs)
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if self.expr is not None:
-            return self.expr._parse(instring, loc, doActions, callPreParse=False)
-        else:
-            raise ParseException("", loc, self.errmsg, self)
-
-    def leaveWhitespace(self):
-        self.skipWhitespace = False
-        self.expr = self.expr.copy()
-        if self.expr is not None:
-            self.expr.leaveWhitespace()
-        return self
-
-    def ignore(self, other):
-        if isinstance(other, Suppress):
-            if other not in self.ignoreExprs:
-                super(ParseElementEnhance, self).ignore(other)
-                if self.expr is not None:
-                    self.expr.ignore(self.ignoreExprs[-1])
-        else:
-            super(ParseElementEnhance, self).ignore(other)
-            if self.expr is not None:
-                self.expr.ignore(self.ignoreExprs[-1])
-        return self
-
-    def streamline(self):
-        super(ParseElementEnhance, self).streamline()
-        if self.expr is not None:
-            self.expr.streamline()
-        return self
-
-    def checkRecursion(self, parseElementList):
-        if self in parseElementList:
-            raise RecursiveGrammarException(parseElementList + [self])
-        subRecCheckList = parseElementList[:] + [self]
-        if self.expr is not None:
-            self.expr.checkRecursion(subRecCheckList)
-
-    def validate(self, validateTrace=None):
-        if validateTrace is None:
-            validateTrace = []
-        tmp = validateTrace[:] + [self]
-        if self.expr is not None:
-            self.expr.validate(tmp)
-        self.checkRecursion([])
-
-    def __str__(self):
-        try:
-            return super(ParseElementEnhance, self).__str__()
-        except Exception:
-            pass
-
-        if self.strRepr is None and self.expr is not None:
-            self.strRepr = "%s:(%s)" % (self.__class__.__name__, _ustr(self.expr))
-        return self.strRepr
-
-
-class FollowedBy(ParseElementEnhance):
-    """Lookahead matching of the given parse expression.
-    ``FollowedBy`` does *not* advance the parsing position within
-    the input string, it only verifies that the specified parse
-    expression matches at the current position.  ``FollowedBy``
-    always returns a null token list. If any results names are defined
-    in the lookahead expression, those *will* be returned for access by
-    name.
-
-    Example::
-
-        # use FollowedBy to match a label only if it is followed by a ':'
-        data_word = Word(alphas)
-        label = data_word + FollowedBy(':')
-        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
-
-        OneOrMore(attr_expr).parseString("shape: SQUARE color: BLACK posn: upper left").pprint()
-
-    prints::
-
-        [['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']]
-    """
-    def __init__(self, expr):
-        super(FollowedBy, self).__init__(expr)
-        self.mayReturnEmpty = True
-
-    def parseImpl(self, instring, loc, doActions=True):
-        # by using self._expr.parse and deleting the contents of the returned ParseResults list
-        # we keep any named results that were defined in the FollowedBy expression
-        _, ret = self.expr._parse(instring, loc, doActions=doActions)
-        del ret[:]
-
-        return loc, ret
-
-
-class PrecededBy(ParseElementEnhance):
-    """Lookbehind matching of the given parse expression.
-    ``PrecededBy`` does not advance the parsing position within the
-    input string, it only verifies that the specified parse expression
-    matches prior to the current position.  ``PrecededBy`` always
-    returns a null token list, but if a results name is defined on the
-    given expression, it is returned.
-
-    Parameters:
-
-     - expr - expression that must match prior to the current parse
-       location
-     - retreat - (default= ``None``) - (int) maximum number of characters
-       to lookbehind prior to the current parse location
-
-    If the lookbehind expression is a string, Literal, Keyword, or
-    a Word or CharsNotIn with a specified exact or maximum length, then
-    the retreat parameter is not required. Otherwise, retreat must be
-    specified to give a maximum number of characters to look back from
-    the current parse position for a lookbehind match.
-
-    Example::
-
-        # VB-style variable names with type prefixes
-        int_var = PrecededBy("#") + pyparsing_common.identifier
-        str_var = PrecededBy("$") + pyparsing_common.identifier
-
-    """
-    def __init__(self, expr, retreat=None):
-        super(PrecededBy, self).__init__(expr)
-        self.expr = self.expr().leaveWhitespace()
-        self.mayReturnEmpty = True
-        self.mayIndexError = False
-        self.exact = False
-        if isinstance(expr, str):
-            retreat = len(expr)
-            self.exact = True
-        elif isinstance(expr, (Literal, Keyword)):
-            retreat = expr.matchLen
-            self.exact = True
-        elif isinstance(expr, (Word, CharsNotIn)) and expr.maxLen != _MAX_INT:
-            retreat = expr.maxLen
-            self.exact = True
-        elif isinstance(expr, _PositionToken):
-            retreat = 0
-            self.exact = True
-        self.retreat = retreat
-        self.errmsg = "not preceded by " + str(expr)
-        self.skipWhitespace = False
-        self.parseAction.append(lambda s, l, t: t.__delitem__(slice(None, None)))
-
-    def parseImpl(self, instring, loc=0, doActions=True):
-        if self.exact:
-            if loc < self.retreat:
-                raise ParseException(instring, loc, self.errmsg)
-            start = loc - self.retreat
-            _, ret = self.expr._parse(instring, start)
-        else:
-            # retreat specified a maximum lookbehind window, iterate
-            test_expr = self.expr + StringEnd()
-            instring_slice = instring[max(0, loc - self.retreat):loc]
-            last_expr = ParseException(instring, loc, self.errmsg)
-            for offset in range(1, min(loc, self.retreat + 1)+1):
-                try:
-                    # print('trying', offset, instring_slice, repr(instring_slice[loc - offset:]))
-                    _, ret = test_expr._parse(instring_slice, len(instring_slice) - offset)
-                except ParseBaseException as pbe:
-                    last_expr = pbe
-                else:
-                    break
-            else:
-                raise last_expr
-        return loc, ret
-
-
-class NotAny(ParseElementEnhance):
-    """Lookahead to disallow matching with the given parse expression.
-    ``NotAny`` does *not* advance the parsing position within the
-    input string, it only verifies that the specified parse expression
-    does *not* match at the current position.  Also, ``NotAny`` does
-    *not* skip over leading whitespace. ``NotAny`` always returns
-    a null token list.  May be constructed using the '~' operator.
-
-    Example::
-
-        AND, OR, NOT = map(CaselessKeyword, "AND OR NOT".split())
-
-        # take care not to mistake keywords for identifiers
-        ident = ~(AND | OR | NOT) + Word(alphas)
-        boolean_term = Optional(NOT) + ident
-
-        # very crude boolean expression - to support parenthesis groups and
-        # operation hierarchy, use infixNotation
-        boolean_expr = boolean_term + ZeroOrMore((AND | OR) + boolean_term)
-
-        # integers that are followed by "." are actually floats
-        integer = Word(nums) + ~Char(".")
-    """
-    def __init__(self, expr):
-        super(NotAny, self).__init__(expr)
-        # ~ self.leaveWhitespace()
-        self.skipWhitespace = False  # do NOT use self.leaveWhitespace(), don't want to propagate to exprs
-        self.mayReturnEmpty = True
-        self.errmsg = "Found unwanted token, " + _ustr(self.expr)
-
-    def parseImpl(self, instring, loc, doActions=True):
-        if self.expr.canParseNext(instring, loc):
-            raise ParseException(instring, loc, self.errmsg, self)
-        return loc, []
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "~{" + _ustr(self.expr) + "}"
-
-        return self.strRepr
-
-class _MultipleMatch(ParseElementEnhance):
-    def __init__(self, expr, stopOn=None):
-        super(_MultipleMatch, self).__init__(expr)
-        self.saveAsList = True
-        ender = stopOn
-        if isinstance(ender, basestring):
-            ender = self._literalStringClass(ender)
-        self.stopOn(ender)
-
-    def stopOn(self, ender):
-        if isinstance(ender, basestring):
-            ender = self._literalStringClass(ender)
-        self.not_ender = ~ender if ender is not None else None
-        return self
-
-    def parseImpl(self, instring, loc, doActions=True):
-        self_expr_parse = self.expr._parse
-        self_skip_ignorables = self._skipIgnorables
-        check_ender = self.not_ender is not None
-        if check_ender:
-            try_not_ender = self.not_ender.tryParse
-
-        # must be at least one (but first see if we are the stopOn sentinel;
-        # if so, fail)
-        if check_ender:
-            try_not_ender(instring, loc)
-        loc, tokens = self_expr_parse(instring, loc, doActions, callPreParse=False)
-        try:
-            hasIgnoreExprs = (not not self.ignoreExprs)
-            while 1:
-                if check_ender:
-                    try_not_ender(instring, loc)
-                if hasIgnoreExprs:
-                    preloc = self_skip_ignorables(instring, loc)
-                else:
-                    preloc = loc
-                loc, tmptokens = self_expr_parse(instring, preloc, doActions)
-                if tmptokens or tmptokens.haskeys():
-                    tokens += tmptokens
-        except (ParseException, IndexError):
-            pass
-
-        return loc, tokens
-
-    def _setResultsName(self, name, listAllMatches=False):
-        if __diag__.warn_ungrouped_named_tokens_in_collection:
-            for e in [self.expr] + getattr(self.expr, 'exprs', []):
-                if isinstance(e, ParserElement) and e.resultsName:
-                    warnings.warn("{0}: setting results name {1!r} on {2} expression "
-                                  "collides with {3!r} on contained expression".format("warn_ungrouped_named_tokens_in_collection",
-                                                                                       name,
-                                                                                       type(self).__name__,
-                                                                                       e.resultsName),
-                                  stacklevel=3)
-
-        return super(_MultipleMatch, self)._setResultsName(name, listAllMatches)
-
-
-class OneOrMore(_MultipleMatch):
-    """Repetition of one or more of the given expression.
-
-    Parameters:
-     - expr - expression that must match one or more times
-     - stopOn - (default= ``None``) - expression for a terminating sentinel
-          (only required if the sentinel would ordinarily match the repetition
-          expression)
-
-    Example::
-
-        data_word = Word(alphas)
-        label = data_word + FollowedBy(':')
-        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))
-
-        text = "shape: SQUARE posn: upper left color: BLACK"
-        OneOrMore(attr_expr).parseString(text).pprint()  # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']]
-
-        # use stopOn attribute for OneOrMore to avoid reading label string as part of the data
-        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
-        OneOrMore(attr_expr).parseString(text).pprint() # Better -> [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]
-
-        # could also be written as
-        (attr_expr * (1,)).parseString(text).pprint()
-    """
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "{" + _ustr(self.expr) + "}..."
-
-        return self.strRepr
-
-class ZeroOrMore(_MultipleMatch):
-    """Optional repetition of zero or more of the given expression.
-
-    Parameters:
-     - expr - expression that must match zero or more times
-     - stopOn - (default= ``None``) - expression for a terminating sentinel
-          (only required if the sentinel would ordinarily match the repetition
-          expression)
-
-    Example: similar to :class:`OneOrMore`
-    """
-    def __init__(self, expr, stopOn=None):
-        super(ZeroOrMore, self).__init__(expr, stopOn=stopOn)
-        self.mayReturnEmpty = True
-
-    def parseImpl(self, instring, loc, doActions=True):
-        try:
-            return super(ZeroOrMore, self).parseImpl(instring, loc, doActions)
-        except (ParseException, IndexError):
-            return loc, []
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "[" + _ustr(self.expr) + "]..."
-
-        return self.strRepr
-
-
-class _NullToken(object):
-    def __bool__(self):
-        return False
-    __nonzero__ = __bool__
-    def __str__(self):
-        return ""
-
-class Optional(ParseElementEnhance):
-    """Optional matching of the given expression.
-
-    Parameters:
-     - expr - expression that must match zero or more times
-     - default (optional) - value to be returned if the optional expression is not found.
-
-    Example::
-
-        # US postal code can be a 5-digit zip, plus optional 4-digit qualifier
-        zip = Combine(Word(nums, exact=5) + Optional('-' + Word(nums, exact=4)))
-        zip.runTests('''
-            # traditional ZIP code
-            12345
-
-            # ZIP+4 form
-            12101-0001
-
-            # invalid ZIP
-            98765-
-            ''')
-
-    prints::
-
-        # traditional ZIP code
-        12345
-        ['12345']
-
-        # ZIP+4 form
-        12101-0001
-        ['12101-0001']
-
-        # invalid ZIP
-        98765-
-             ^
-        FAIL: Expected end of text (at char 5), (line:1, col:6)
-    """
-    __optionalNotMatched = _NullToken()
-
-    def __init__(self, expr, default=__optionalNotMatched):
-        super(Optional, self).__init__(expr, savelist=False)
-        self.saveAsList = self.expr.saveAsList
-        self.defaultValue = default
-        self.mayReturnEmpty = True
-
-    def parseImpl(self, instring, loc, doActions=True):
-        try:
-            loc, tokens = self.expr._parse(instring, loc, doActions, callPreParse=False)
-        except (ParseException, IndexError):
-            if self.defaultValue is not self.__optionalNotMatched:
-                if self.expr.resultsName:
-                    tokens = ParseResults([self.defaultValue])
-                    tokens[self.expr.resultsName] = self.defaultValue
-                else:
-                    tokens = [self.defaultValue]
-            else:
-                tokens = []
-        return loc, tokens
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-
-        if self.strRepr is None:
-            self.strRepr = "[" + _ustr(self.expr) + "]"
-
-        return self.strRepr
-
-class SkipTo(ParseElementEnhance):
-    """Token for skipping over all undefined text until the matched
-    expression is found.
-
-    Parameters:
-     - expr - target expression marking the end of the data to be skipped
-     - include - (default= ``False``) if True, the target expression is also parsed
-          (the skipped text and target expression are returned as a 2-element list).
-     - ignore - (default= ``None``) used to define grammars (typically quoted strings and
-          comments) that might contain false matches to the target expression
-     - failOn - (default= ``None``) define expressions that are not allowed to be
-          included in the skipped test; if found before the target expression is found,
-          the SkipTo is not a match
-
-    Example::
-
-        report = '''
-            Outstanding Issues Report - 1 Jan 2000
-
-               # | Severity | Description                               |  Days Open
-            -----+----------+-------------------------------------------+-----------
-             101 | Critical | Intermittent system crash                 |          6
-              94 | Cosmetic | Spelling error on Login ('log|n')         |         14
-              79 | Minor    | System slow when running too many reports |         47
-            '''
-        integer = Word(nums)
-        SEP = Suppress('|')
-        # use SkipTo to simply match everything up until the next SEP
-        # - ignore quoted strings, so that a '|' character inside a quoted string does not match
-        # - parse action will call token.strip() for each matched token, i.e., the description body
-        string_data = SkipTo(SEP, ignore=quotedString)
-        string_data.setParseAction(tokenMap(str.strip))
-        ticket_expr = (integer("issue_num") + SEP
-                      + string_data("sev") + SEP
-                      + string_data("desc") + SEP
-                      + integer("days_open"))
-
-        for tkt in ticket_expr.searchString(report):
-            print tkt.dump()
-
-    prints::
-
-        ['101', 'Critical', 'Intermittent system crash', '6']
-        - days_open: 6
-        - desc: Intermittent system crash
-        - issue_num: 101
-        - sev: Critical
-        ['94', 'Cosmetic', "Spelling error on Login ('log|n')", '14']
-        - days_open: 14
-        - desc: Spelling error on Login ('log|n')
-        - issue_num: 94
-        - sev: Cosmetic
-        ['79', 'Minor', 'System slow when running too many reports', '47']
-        - days_open: 47
-        - desc: System slow when running too many reports
-        - issue_num: 79
-        - sev: Minor
-    """
-    def __init__(self, other, include=False, ignore=None, failOn=None):
-        super(SkipTo, self).__init__(other)
-        self.ignoreExpr = ignore
-        self.mayReturnEmpty = True
-        self.mayIndexError = False
-        self.includeMatch = include
-        self.saveAsList = False
-        if isinstance(failOn, basestring):
-            self.failOn = self._literalStringClass(failOn)
-        else:
-            self.failOn = failOn
-        self.errmsg = "No match found for " + _ustr(self.expr)
-
-    def parseImpl(self, instring, loc, doActions=True):
-        startloc = loc
-        instrlen = len(instring)
-        expr = self.expr
-        expr_parse = self.expr._parse
-        self_failOn_canParseNext = self.failOn.canParseNext if self.failOn is not None else None
-        self_ignoreExpr_tryParse = self.ignoreExpr.tryParse if self.ignoreExpr is not None else None
-
-        tmploc = loc
-        while tmploc <= instrlen:
-            if self_failOn_canParseNext is not None:
-                # break if failOn expression matches
-                if self_failOn_canParseNext(instring, tmploc):
-                    break
-
-            if self_ignoreExpr_tryParse is not None:
-                # advance past ignore expressions
-                while 1:
-                    try:
-                        tmploc = self_ignoreExpr_tryParse(instring, tmploc)
-                    except ParseBaseException:
-                        break
-
-            try:
-                expr_parse(instring, tmploc, doActions=False, callPreParse=False)
-            except (ParseException, IndexError):
-                # no match, advance loc in string
-                tmploc += 1
-            else:
-                # matched skipto expr, done
-                break
-
-        else:
-            # ran off the end of the input string without matching skipto expr, fail
-            raise ParseException(instring, loc, self.errmsg, self)
-
-        # build up return values
-        loc = tmploc
-        skiptext = instring[startloc:loc]
-        skipresult = ParseResults(skiptext)
-
-        if self.includeMatch:
-            loc, mat = expr_parse(instring, loc, doActions, callPreParse=False)
-            skipresult += mat
-
-        return loc, skipresult
-
-class Forward(ParseElementEnhance):
-    """Forward declaration of an expression to be defined later -
-    used for recursive grammars, such as algebraic infix notation.
-    When the expression is known, it is assigned to the ``Forward``
-    variable using the '<<' operator.
-
-    Note: take care when assigning to ``Forward`` not to overlook
-    precedence of operators.
-
-    Specifically, '|' has a lower precedence than '<<', so that::
-
-        fwdExpr << a | b | c
-
-    will actually be evaluated as::
-
-        (fwdExpr << a) | b | c
-
-    thereby leaving b and c out as parseable alternatives.  It is recommended that you
-    explicitly group the values inserted into the ``Forward``::
-
-        fwdExpr << (a | b | c)
-
-    Converting to use the '<<=' operator instead will avoid this problem.
-
-    See :class:`ParseResults.pprint` for an example of a recursive
-    parser created using ``Forward``.
-    """
-    def __init__(self, other=None):
-        super(Forward, self).__init__(other, savelist=False)
-
-    def __lshift__(self, other):
-        if isinstance(other, basestring):
-            other = self._literalStringClass(other)
-        self.expr = other
-        self.strRepr = None
-        self.mayIndexError = self.expr.mayIndexError
-        self.mayReturnEmpty = self.expr.mayReturnEmpty
-        self.setWhitespaceChars(self.expr.whiteChars)
-        self.skipWhitespace = self.expr.skipWhitespace
-        self.saveAsList = self.expr.saveAsList
-        self.ignoreExprs.extend(self.expr.ignoreExprs)
-        return self
-
-    def __ilshift__(self, other):
-        return self << other
-
-    def leaveWhitespace(self):
-        self.skipWhitespace = False
-        return self
-
-    def streamline(self):
-        if not self.streamlined:
-            self.streamlined = True
-            if self.expr is not None:
-                self.expr.streamline()
-        return self
-
-    def validate(self, validateTrace=None):
-        if validateTrace is None:
-            validateTrace = []
-
-        if self not in validateTrace:
-            tmp = validateTrace[:] + [self]
-            if self.expr is not None:
-                self.expr.validate(tmp)
-        self.checkRecursion([])
-
-    def __str__(self):
-        if hasattr(self, "name"):
-            return self.name
-        if self.strRepr is not None:
-            return self.strRepr
-
-        # Avoid infinite recursion by setting a temporary strRepr
-        self.strRepr = ": ..."
-
-        # Use the string representation of main expression.
-        retString = '...'
-        try:
-            if self.expr is not None:
-                retString = _ustr(self.expr)[:1000]
-            else:
-                retString = "None"
-        finally:
-            self.strRepr = self.__class__.__name__ + ": " + retString
-        return self.strRepr
-
-    def copy(self):
-        if self.expr is not None:
-            return super(Forward, self).copy()
-        else:
-            ret = Forward()
-            ret <<= self
-            return ret
-
-    def _setResultsName(self, name, listAllMatches=False):
-        if __diag__.warn_name_set_on_empty_Forward:
-            if self.expr is None:
-                warnings.warn("{0}: setting results name {0!r} on {1} expression "
-                              "that has no contained expression".format("warn_name_set_on_empty_Forward",
-                                                                        name,
-                                                                        type(self).__name__),
-                              stacklevel=3)
-
-        return super(Forward, self)._setResultsName(name, listAllMatches)
-
-class TokenConverter(ParseElementEnhance):
-    """
-    Abstract subclass of :class:`ParseExpression`, for converting parsed results.
-    """
-    def __init__(self, expr, savelist=False):
-        super(TokenConverter, self).__init__(expr)  # , savelist)
-        self.saveAsList = False
-
-class Combine(TokenConverter):
-    """Converter to concatenate all matching tokens to a single string.
-    By default, the matching patterns must also be contiguous in the
-    input string; this can be disabled by specifying
-    ``'adjacent=False'`` in the constructor.
-
-    Example::
-
-        real = Word(nums) + '.' + Word(nums)
-        print(real.parseString('3.1416')) # -> ['3', '.', '1416']
-        # will also erroneously match the following
-        print(real.parseString('3. 1416')) # -> ['3', '.', '1416']
-
-        real = Combine(Word(nums) + '.' + Word(nums))
-        print(real.parseString('3.1416')) # -> ['3.1416']
-        # no match when there are internal spaces
-        print(real.parseString('3. 1416')) # -> Exception: Expected W:(0123...)
-    """
-    def __init__(self, expr, joinString="", adjacent=True):
-        super(Combine, self).__init__(expr)
-        # suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself
-        if adjacent:
-            self.leaveWhitespace()
-        self.adjacent = adjacent
-        self.skipWhitespace = True
-        self.joinString = joinString
-        self.callPreparse = True
-
-    def ignore(self, other):
-        if self.adjacent:
-            ParserElement.ignore(self, other)
-        else:
-            super(Combine, self).ignore(other)
-        return self
-
-    def postParse(self, instring, loc, tokenlist):
-        retToks = tokenlist.copy()
-        del retToks[:]
-        retToks += ParseResults(["".join(tokenlist._asStringList(self.joinString))], modal=self.modalResults)
-
-        if self.resultsName and retToks.haskeys():
-            return [retToks]
-        else:
-            return retToks
-
-class Group(TokenConverter):
-    """Converter to return the matched tokens as a list - useful for
-    returning tokens of :class:`ZeroOrMore` and :class:`OneOrMore` expressions.
-
-    Example::
-
-        ident = Word(alphas)
-        num = Word(nums)
-        term = ident | num
-        func = ident + Optional(delimitedList(term))
-        print(func.parseString("fn a, b, 100"))  # -> ['fn', 'a', 'b', '100']
-
-        func = ident + Group(Optional(delimitedList(term)))
-        print(func.parseString("fn a, b, 100"))  # -> ['fn', ['a', 'b', '100']]
-    """
-    def __init__(self, expr):
-        super(Group, self).__init__(expr)
-        self.saveAsList = True
-
-    def postParse(self, instring, loc, tokenlist):
-        return [tokenlist]
-
-class Dict(TokenConverter):
-    """Converter to return a repetitive expression as a list, but also
-    as a dictionary. Each element can also be referenced using the first
-    token in the expression as its key. Useful for tabular report
-    scraping when the first column can be used as a item key.
-
-    Example::
-
-        data_word = Word(alphas)
-        label = data_word + FollowedBy(':')
-        attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join))
-
-        text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
-        attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
-
-        # print attributes as plain groups
-        print(OneOrMore(attr_expr).parseString(text).dump())
-
-        # instead of OneOrMore(expr), parse using Dict(OneOrMore(Group(expr))) - Dict will auto-assign names
-        result = Dict(OneOrMore(Group(attr_expr))).parseString(text)
-        print(result.dump())
-
-        # access named fields as dict entries, or output as dict
-        print(result['shape'])
-        print(result.asDict())
-
-    prints::
-
-        ['shape', 'SQUARE', 'posn', 'upper left', 'color', 'light blue', 'texture', 'burlap']
-        [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
-        - color: light blue
-        - posn: upper left
-        - shape: SQUARE
-        - texture: burlap
-        SQUARE
-        {'color': 'light blue', 'posn': 'upper left', 'texture': 'burlap', 'shape': 'SQUARE'}
-
-    See more examples at :class:`ParseResults` of accessing fields by results name.
-    """
-    def __init__(self, expr):
-        super(Dict, self).__init__(expr)
-        self.saveAsList = True
-
-    def postParse(self, instring, loc, tokenlist):
-        for i, tok in enumerate(tokenlist):
-            if len(tok) == 0:
-                continue
-            ikey = tok[0]
-            if isinstance(ikey, int):
-                ikey = _ustr(tok[0]).strip()
-            if len(tok) == 1:
-                tokenlist[ikey] = _ParseResultsWithOffset("", i)
-            elif len(tok) == 2 and not isinstance(tok[1], ParseResults):
-                tokenlist[ikey] = _ParseResultsWithOffset(tok[1], i)
-            else:
-                dictvalue = tok.copy()  # ParseResults(i)
-                del dictvalue[0]
-                if len(dictvalue) != 1 or (isinstance(dictvalue, ParseResults) and dictvalue.haskeys()):
-                    tokenlist[ikey] = _ParseResultsWithOffset(dictvalue, i)
-                else:
-                    tokenlist[ikey] = _ParseResultsWithOffset(dictvalue[0], i)
-
-        if self.resultsName:
-            return [tokenlist]
-        else:
-            return tokenlist
-
-
-class Suppress(TokenConverter):
-    """Converter for ignoring the results of a parsed expression.
-
-    Example::
-
-        source = "a, b, c,d"
-        wd = Word(alphas)
-        wd_list1 = wd + ZeroOrMore(',' + wd)
-        print(wd_list1.parseString(source))
-
-        # often, delimiters that are useful during parsing are just in the
-        # way afterward - use Suppress to keep them out of the parsed output
-        wd_list2 = wd + ZeroOrMore(Suppress(',') + wd)
-        print(wd_list2.parseString(source))
-
-    prints::
-
-        ['a', ',', 'b', ',', 'c', ',', 'd']
-        ['a', 'b', 'c', 'd']
-
-    (See also :class:`delimitedList`.)
-    """
-    def postParse(self, instring, loc, tokenlist):
-        return []
-
-    def suppress(self):
-        return self
-
-
-class OnlyOnce(object):
-    """Wrapper for parse actions, to ensure they are only called once.
-    """
-    def __init__(self, methodCall):
-        self.callable = _trim_arity(methodCall)
-        self.called = False
-    def __call__(self, s, l, t):
-        if not self.called:
-            results = self.callable(s, l, t)
-            self.called = True
-            return results
-        raise ParseException(s, l, "")
-    def reset(self):
-        self.called = False
-
-def traceParseAction(f):
-    """Decorator for debugging parse actions.
-
-    When the parse action is called, this decorator will print
-    ``">> entering method-name(line:<current_source_line>, <parse_location>, <matched_tokens>)"``.
-    When the parse action completes, the decorator will print
-    ``"<<"`` followed by the returned value, or any exception that the parse action raised.
-
-    Example::
-
-        wd = Word(alphas)
-
-        @traceParseAction
-        def remove_duplicate_chars(tokens):
-            return ''.join(sorted(set(''.join(tokens))))
-
-        wds = OneOrMore(wd).setParseAction(remove_duplicate_chars)
-        print(wds.parseString("slkdjs sld sldd sdlf sdljf"))
-
-    prints::
-
-        >>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf', 0, (['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {}))
-        <<leaving remove_duplicate_chars (ret: 'dfjkls')
-        ['dfjkls']
-    """
-    f = _trim_arity(f)
-    def z(*paArgs):
-        thisFunc = f.__name__
-        s, l, t = paArgs[-3:]
-        if len(paArgs) > 3:
-            thisFunc = paArgs[0].__class__.__name__ + '.' + thisFunc
-        sys.stderr.write(">>entering %s(line: '%s', %d, %r)\n" % (thisFunc, line(l, s), l, t))
-        try:
-            ret = f(*paArgs)
-        except Exception as exc:
-            sys.stderr.write("<<leaving %s (exception: %s)\n" % (thisFunc, exc))
-            raise
-        sys.stderr.write("<<leaving %s (ret: %r)\n" % (thisFunc, ret))
-        return ret
-    try:
-        z.__name__ = f.__name__
-    except AttributeError:
-        pass
-    return z
-
-#
-# global helpers
-#
-def delimitedList(expr, delim=",", combine=False):
-    """Helper to define a delimited list of expressions - the delimiter
-    defaults to ','. By default, the list elements and delimiters can
-    have intervening whitespace, and comments, but this can be
-    overridden by passing ``combine=True`` in the constructor. If
-    ``combine`` is set to ``True``, the matching tokens are
-    returned as a single token string, with the delimiters included;
-    otherwise, the matching tokens are returned as a list of tokens,
-    with the delimiters suppressed.
-
-    Example::
-
-        delimitedList(Word(alphas)).parseString("aa,bb,cc") # -> ['aa', 'bb', 'cc']
-        delimitedList(Word(hexnums), delim=':', combine=True).parseString("AA:BB:CC:DD:EE") # -> ['AA:BB:CC:DD:EE']
-    """
-    dlName = _ustr(expr) + " [" + _ustr(delim) + " " + _ustr(expr) + "]..."
-    if combine:
-        return Combine(expr + ZeroOrMore(delim + expr)).setName(dlName)
-    else:
-        return (expr + ZeroOrMore(Suppress(delim) + expr)).setName(dlName)
-
-def countedArray(expr, intExpr=None):
-    """Helper to define a counted list of expressions.
-
-    This helper defines a pattern of the form::
-
-        integer expr expr expr...
-
-    where the leading integer tells how many expr expressions follow.
-    The matched tokens returns the array of expr tokens as a list - the
-    leading count token is suppressed.
-
-    If ``intExpr`` is specified, it should be a pyparsing expression
-    that produces an integer value.
-
-    Example::
-
-        countedArray(Word(alphas)).parseString('2 ab cd ef')  # -> ['ab', 'cd']
-
-        # in this parser, the leading integer value is given in binary,
-        # '10' indicating that 2 values are in the array
-        binaryConstant = Word('01').setParseAction(lambda t: int(t[0], 2))
-        countedArray(Word(alphas), intExpr=binaryConstant).parseString('10 ab cd ef')  # -> ['ab', 'cd']
-    """
-    arrayExpr = Forward()
-    def countFieldParseAction(s, l, t):
-        n = t[0]
-        arrayExpr << (n and Group(And([expr] * n)) or Group(empty))
-        return []
-    if intExpr is None:
-        intExpr = Word(nums).setParseAction(lambda t: int(t[0]))
-    else:
-        intExpr = intExpr.copy()
-    intExpr.setName("arrayLen")
-    intExpr.addParseAction(countFieldParseAction, callDuringTry=True)
-    return (intExpr + arrayExpr).setName('(len) ' + _ustr(expr) + '...')
-
-def _flatten(L):
-    ret = []
-    for i in L:
-        if isinstance(i, list):
-            ret.extend(_flatten(i))
-        else:
-            ret.append(i)
-    return ret
-
-def matchPreviousLiteral(expr):
-    """Helper to define an expression that is indirectly defined from
-    the tokens matched in a previous expression, that is, it looks for
-    a 'repeat' of a previous expression.  For example::
-
-        first = Word(nums)
-        second = matchPreviousLiteral(first)
-        matchExpr = first + ":" + second
-
-    will match ``"1:1"``, but not ``"1:2"``.  Because this
-    matches a previous literal, will also match the leading
-    ``"1:1"`` in ``"1:10"``. If this is not desired, use
-    :class:`matchPreviousExpr`. Do *not* use with packrat parsing
-    enabled.
-    """
-    rep = Forward()
-    def copyTokenToRepeater(s, l, t):
-        if t:
-            if len(t) == 1:
-                rep << t[0]
-            else:
-                # flatten t tokens
-                tflat = _flatten(t.asList())
-                rep << And(Literal(tt) for tt in tflat)
-        else:
-            rep << Empty()
-    expr.addParseAction(copyTokenToRepeater, callDuringTry=True)
-    rep.setName('(prev) ' + _ustr(expr))
-    return rep
-
-def matchPreviousExpr(expr):
-    """Helper to define an expression that is indirectly defined from
-    the tokens matched in a previous expression, that is, it looks for
-    a 'repeat' of a previous expression.  For example::
-
-        first = Word(nums)
-        second = matchPreviousExpr(first)
-        matchExpr = first + ":" + second
-
-    will match ``"1:1"``, but not ``"1:2"``.  Because this
-    matches by expressions, will *not* match the leading ``"1:1"``
-    in ``"1:10"``; the expressions are evaluated first, and then
-    compared, so ``"1"`` is compared with ``"10"``. Do *not* use
-    with packrat parsing enabled.
-    """
-    rep = Forward()
-    e2 = expr.copy()
-    rep <<= e2
-    def copyTokenToRepeater(s, l, t):
-        matchTokens = _flatten(t.asList())
-        def mustMatchTheseTokens(s, l, t):
-            theseTokens = _flatten(t.asList())
-            if theseTokens != matchTokens:
-                raise ParseException('', 0, '')
-        rep.setParseAction(mustMatchTheseTokens, callDuringTry=True)
-    expr.addParseAction(copyTokenToRepeater, callDuringTry=True)
-    rep.setName('(prev) ' + _ustr(expr))
-    return rep
-
-def _escapeRegexRangeChars(s):
-    # ~  escape these chars: ^-[]
-    for c in r"\^-[]":
-        s = s.replace(c, _bslash + c)
-    s = s.replace("\n", r"\n")
-    s = s.replace("\t", r"\t")
-    return _ustr(s)
-
-def oneOf(strs, caseless=False, useRegex=True, asKeyword=False):
-    """Helper to quickly define a set of alternative Literals, and makes
-    sure to do longest-first testing when there is a conflict,
-    regardless of the input order, but returns
-    a :class:`MatchFirst` for best performance.
-
-    Parameters:
-
-     - strs - a string of space-delimited literals, or a collection of
-       string literals
-     - caseless - (default= ``False``) - treat all literals as
-       caseless
-     - useRegex - (default= ``True``) - as an optimization, will
-       generate a Regex object; otherwise, will generate
-       a :class:`MatchFirst` object (if ``caseless=True`` or ``asKeyword=True``, or if
-       creating a :class:`Regex` raises an exception)
-     - asKeyword - (default=``False``) - enforce Keyword-style matching on the
-       generated expressions
-
-    Example::
-
-        comp_oper = oneOf("< = > <= >= !=")
-        var = Word(alphas)
-        number = Word(nums)
-        term = var | number
-        comparison_expr = term + comp_oper + term
-        print(comparison_expr.searchString("B = 12  AA=23 B<=AA AA>12"))
-
-    prints::
-
-        [['B', '=', '12'], ['AA', '=', '23'], ['B', '<=', 'AA'], ['AA', '>', '12']]
-    """
-    if isinstance(caseless, basestring):
-        warnings.warn("More than one string argument passed to oneOf, pass "
-                      "choices as a list or space-delimited string", stacklevel=2)
-
-    if caseless:
-        isequal = (lambda a, b: a.upper() == b.upper())
-        masks = (lambda a, b: b.upper().startswith(a.upper()))
-        parseElementClass = CaselessKeyword if asKeyword else CaselessLiteral
-    else:
-        isequal = (lambda a, b: a == b)
-        masks = (lambda a, b: b.startswith(a))
-        parseElementClass = Keyword if asKeyword else Literal
-
-    symbols = []
-    if isinstance(strs, basestring):
-        symbols = strs.split()
-    elif isinstance(strs, Iterable):
-        symbols = list(strs)
-    else:
-        warnings.warn("Invalid argument to oneOf, expected string or iterable",
-                      SyntaxWarning, stacklevel=2)
-    if not symbols:
-        return NoMatch()
-
-    if not asKeyword:
-        # if not producing keywords, need to reorder to take care to avoid masking
-        # longer choices with shorter ones
-        i = 0
-        while i < len(symbols) - 1:
-            cur = symbols[i]
-            for j, other in enumerate(symbols[i + 1:]):
-                if isequal(other, cur):
-                    del symbols[i + j + 1]
-                    break
-                elif masks(cur, other):
-                    del symbols[i + j + 1]
-                    symbols.insert(i, other)
-                    break
-            else:
-                i += 1
-
-    if not (caseless or asKeyword) and useRegex:
-        # ~ print (strs, "->", "|".join([_escapeRegexChars(sym) for sym in symbols]))
-        try:
-            if len(symbols) == len("".join(symbols)):
-                return Regex("[%s]" % "".join(_escapeRegexRangeChars(sym) for sym in symbols)).setName(' | '.join(symbols))
-            else:
-                return Regex("|".join(re.escape(sym) for sym in symbols)).setName(' | '.join(symbols))
-        except Exception:
-            warnings.warn("Exception creating Regex for oneOf, building MatchFirst",
-                    SyntaxWarning, stacklevel=2)
-
-    # last resort, just use MatchFirst
-    return MatchFirst(parseElementClass(sym) for sym in symbols).setName(' | '.join(symbols))
-
-def dictOf(key, value):
-    """Helper to easily and clearly define a dictionary by specifying
-    the respective patterns for the key and value.  Takes care of
-    defining the :class:`Dict`, :class:`ZeroOrMore`, and
-    :class:`Group` tokens in the proper order.  The key pattern
-    can include delimiting markers or punctuation, as long as they are
-    suppressed, thereby leaving the significant key text.  The value
-    pattern can include named results, so that the :class:`Dict` results
-    can include named token fields.
-
-    Example::
-
-        text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
-        attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join))
-        print(OneOrMore(attr_expr).parseString(text).dump())
-
-        attr_label = label
-        attr_value = Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join)
-
-        # similar to Dict, but simpler call format
-        result = dictOf(attr_label, attr_value).parseString(text)
-        print(result.dump())
-        print(result['shape'])
-        print(result.shape)  # object attribute access works too
-        print(result.asDict())
-
-    prints::
-
-        [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
-        - color: light blue
-        - posn: upper left
-        - shape: SQUARE
-        - texture: burlap
-        SQUARE
-        SQUARE
-        {'color': 'light blue', 'shape': 'SQUARE', 'posn': 'upper left', 'texture': 'burlap'}
-    """
-    return Dict(OneOrMore(Group(key + value)))
-
-def originalTextFor(expr, asString=True):
-    """Helper to return the original, untokenized text for a given
-    expression.  Useful to restore the parsed fields of an HTML start
-    tag into the raw tag text itself, or to revert separate tokens with
-    intervening whitespace back to the original matching input text. By
-    default, returns astring containing the original parsed text.
-
-    If the optional ``asString`` argument is passed as
-    ``False``, then the return value is
-    a :class:`ParseResults` containing any results names that
-    were originally matched, and a single token containing the original
-    matched text from the input string.  So if the expression passed to
-    :class:`originalTextFor` contains expressions with defined
-    results names, you must set ``asString`` to ``False`` if you
-    want to preserve those results name values.
-
-    Example::
-
-        src = "this is test <b> bold <i>text</i> </b> normal text "
-        for tag in ("b", "i"):
-            opener, closer = makeHTMLTags(tag)
-            patt = originalTextFor(opener + SkipTo(closer) + closer)
-            print(patt.searchString(src)[0])
-
-    prints::
-
-        ['<b> bold <i>text</i> </b>']
-        ['<i>text</i>']
-    """
-    locMarker = Empty().setParseAction(lambda s, loc, t: loc)
-    endlocMarker = locMarker.copy()
-    endlocMarker.callPreparse = False
-    matchExpr = locMarker("_original_start") + expr + endlocMarker("_original_end")
-    if asString:
-        extractText = lambda s, l, t: s[t._original_start: t._original_end]
-    else:
-        def extractText(s, l, t):
-            t[:] = [s[t.pop('_original_start'):t.pop('_original_end')]]
-    matchExpr.setParseAction(extractText)
-    matchExpr.ignoreExprs = expr.ignoreExprs
-    return matchExpr
-
-def ungroup(expr):
-    """Helper to undo pyparsing's default grouping of And expressions,
-    even if all but one are non-empty.
-    """
-    return TokenConverter(expr).addParseAction(lambda t: t[0])
-
-def locatedExpr(expr):
-    """Helper to decorate a returned token with its starting and ending
-    locations in the input string.
-
-    This helper adds the following results names:
-
-     - locn_start = location where matched expression begins
-     - locn_end = location where matched expression ends
-     - value = the actual parsed results
-
-    Be careful if the input text contains ``<TAB>`` characters, you
-    may want to call :class:`ParserElement.parseWithTabs`
-
-    Example::
-
-        wd = Word(alphas)
-        for match in locatedExpr(wd).searchString("ljsdf123lksdjjf123lkkjj1222"):
-            print(match)
-
-    prints::
-
-        [[0, 'ljsdf', 5]]
-        [[8, 'lksdjjf', 15]]
-        [[18, 'lkkjj', 23]]
-    """
-    locator = Empty().setParseAction(lambda s, l, t: l)
-    return Group(locator("locn_start") + expr("value") + locator.copy().leaveWhitespace()("locn_end"))
-
-
-# convenience constants for positional expressions
-empty       = Empty().setName("empty")
-lineStart   = LineStart().setName("lineStart")
-lineEnd     = LineEnd().setName("lineEnd")
-stringStart = StringStart().setName("stringStart")
-stringEnd   = StringEnd().setName("stringEnd")
-
-_escapedPunc = Word(_bslash, r"\[]-*.$+^?()~ ", exact=2).setParseAction(lambda s, l, t: t[0][1])
-_escapedHexChar = Regex(r"\\0?[xX][0-9a-fA-F]+").setParseAction(lambda s, l, t: unichr(int(t[0].lstrip(r'\0x'), 16)))
-_escapedOctChar = Regex(r"\\0[0-7]+").setParseAction(lambda s, l, t: unichr(int(t[0][1:], 8)))
-_singleChar = _escapedPunc | _escapedHexChar | _escapedOctChar | CharsNotIn(r'\]', exact=1)
-_charRange = Group(_singleChar + Suppress("-") + _singleChar)
-_reBracketExpr = Literal("[") + Optional("^").setResultsName("negate") + Group(OneOrMore(_charRange | _singleChar)).setResultsName("body") + "]"
-
-def srange(s):
-    r"""Helper to easily define string ranges for use in Word
-    construction. Borrows syntax from regexp '[]' string range
-    definitions::
-
-        srange("[0-9]")   -> "0123456789"
-        srange("[a-z]")   -> "abcdefghijklmnopqrstuvwxyz"
-        srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"
-
-    The input string must be enclosed in []'s, and the returned string
-    is the expanded character set joined into a single string. The
-    values enclosed in the []'s may be:
-
-     - a single character
-     - an escaped character with a leading backslash (such as ``\-``
-       or ``\]``)
-     - an escaped hex character with a leading ``'\x'``
-       (``\x21``, which is a ``'!'`` character) (``\0x##``
-       is also supported for backwards compatibility)
-     - an escaped octal character with a leading ``'\0'``
-       (``\041``, which is a ``'!'`` character)
-     - a range of any of the above, separated by a dash (``'a-z'``,
-       etc.)
-     - any combination of the above (``'aeiouy'``,
-       ``'a-zA-Z0-9_$'``, etc.)
-    """
-    _expanded = lambda p: p if not isinstance(p, ParseResults) else ''.join(unichr(c) for c in range(ord(p[0]), ord(p[1]) + 1))
-    try:
-        return "".join(_expanded(part) for part in _reBracketExpr.parseString(s).body)
-    except Exception:
-        return ""
-
-def matchOnlyAtCol(n):
-    """Helper method for defining parse actions that require matching at
-    a specific column in the input text.
-    """
-    def verifyCol(strg, locn, toks):
-        if col(locn, strg) != n:
-            raise ParseException(strg, locn, "matched token not at column %d" % n)
-    return verifyCol
-
-def replaceWith(replStr):
-    """Helper method for common parse actions that simply return
-    a literal value.  Especially useful when used with
-    :class:`transformString<ParserElement.transformString>` ().
-
-    Example::
-
-        num = Word(nums).setParseAction(lambda toks: int(toks[0]))
-        na = oneOf("N/A NA").setParseAction(replaceWith(math.nan))
-        term = na | num
-
-        OneOrMore(term).parseString("324 234 N/A 234") # -> [324, 234, nan, 234]
-    """
-    return lambda s, l, t: [replStr]
-
-def removeQuotes(s, l, t):
-    """Helper parse action for removing quotation marks from parsed
-    quoted strings.
-
-    Example::
-
-        # by default, quotation marks are included in parsed results
-        quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["'Now is the Winter of our Discontent'"]
-
-        # use removeQuotes to strip quotation marks from parsed results
-        quotedString.setParseAction(removeQuotes)
-        quotedString.parseString("'Now is the Winter of our Discontent'") # -> ["Now is the Winter of our Discontent"]
-    """
-    return t[0][1:-1]
-
-def tokenMap(func, *args):
-    """Helper to define a parse action by mapping a function to all
-    elements of a ParseResults list. If any additional args are passed,
-    they are forwarded to the given function as additional arguments
-    after the token, as in
-    ``hex_integer = Word(hexnums).setParseAction(tokenMap(int, 16))``,
-    which will convert the parsed data to an integer using base 16.
-
-    Example (compare the last to example in :class:`ParserElement.transformString`::
-
-        hex_ints = OneOrMore(Word(hexnums)).setParseAction(tokenMap(int, 16))
-        hex_ints.runTests('''
-            00 11 22 aa FF 0a 0d 1a
-            ''')
-
-        upperword = Word(alphas).setParseAction(tokenMap(str.upper))
-        OneOrMore(upperword).runTests('''
-            my kingdom for a horse
-            ''')
-
-        wd = Word(alphas).setParseAction(tokenMap(str.title))
-        OneOrMore(wd).setParseAction(' '.join).runTests('''
-            now is the winter of our discontent made glorious summer by this sun of york
-            ''')
-
-    prints::
-
-        00 11 22 aa FF 0a 0d 1a
-        [0, 17, 34, 170, 255, 10, 13, 26]
-
-        my kingdom for a horse
-        ['MY', 'KINGDOM', 'FOR', 'A', 'HORSE']
-
-        now is the winter of our discontent made glorious summer by this sun of york
-        ['Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York']
-    """
-    def pa(s, l, t):
-        return [func(tokn, *args) for tokn in t]
-
-    try:
-        func_name = getattr(func, '__name__',
-                            getattr(func, '__class__').__name__)
-    except Exception:
-        func_name = str(func)
-    pa.__name__ = func_name
-
-    return pa
-
-upcaseTokens = tokenMap(lambda t: _ustr(t).upper())
-"""(Deprecated) Helper parse action to convert tokens to upper case.
-Deprecated in favor of :class:`pyparsing_common.upcaseTokens`"""
-
-downcaseTokens = tokenMap(lambda t: _ustr(t).lower())
-"""(Deprecated) Helper parse action to convert tokens to lower case.
-Deprecated in favor of :class:`pyparsing_common.downcaseTokens`"""
-
-def _makeTags(tagStr, xml,
-              suppress_LT=Suppress("<"),
-              suppress_GT=Suppress(">")):
-    """Internal helper to construct opening and closing tag expressions, given a tag name"""
-    if isinstance(tagStr, basestring):
-        resname = tagStr
-        tagStr = Keyword(tagStr, caseless=not xml)
-    else:
-        resname = tagStr.name
-
-    tagAttrName = Word(alphas, alphanums + "_-:")
-    if xml:
-        tagAttrValue = dblQuotedString.copy().setParseAction(removeQuotes)
-        openTag = (suppress_LT
-                   + tagStr("tag")
-                   + Dict(ZeroOrMore(Group(tagAttrName + Suppress("=") + tagAttrValue)))
-                   + Optional("/", default=[False])("empty").setParseAction(lambda s, l, t: t[0] == '/')
-                   + suppress_GT)
-    else:
-        tagAttrValue = quotedString.copy().setParseAction(removeQuotes) | Word(printables, excludeChars=">")
-        openTag = (suppress_LT
-                   + tagStr("tag")
-                   + Dict(ZeroOrMore(Group(tagAttrName.setParseAction(downcaseTokens)
-                                           + Optional(Suppress("=") + tagAttrValue))))
-                   + Optional("/", default=[False])("empty").setParseAction(lambda s, l, t: t[0] == '/')
-                   + suppress_GT)
-    closeTag = Combine(_L("</") + tagStr + ">", adjacent=False)
-
-    openTag.setName("<%s>" % resname)
-    # add start<tagname> results name in parse action now that ungrouped names are not reported at two levels
-    openTag.addParseAction(lambda t: t.__setitem__("start" + "".join(resname.replace(":", " ").title().split()), t.copy()))
-    closeTag = closeTag("end" + "".join(resname.replace(":", " ").title().split())).setName("</%s>" % resname)
-    openTag.tag = resname
-    closeTag.tag = resname
-    openTag.tag_body = SkipTo(closeTag())
-    return openTag, closeTag
-
-def makeHTMLTags(tagStr):
-    """Helper to construct opening and closing tag expressions for HTML,
-    given a tag name. Matches tags in either upper or lower case,
-    attributes with namespaces and with quoted or unquoted values.
-
-    Example::
-
-        text = '<td>More info at the <a href="https://github.com/pyparsing/pyparsing/wiki">pyparsing</a> wiki page</td>'
-        # makeHTMLTags returns pyparsing expressions for the opening and
-        # closing tags as a 2-tuple
-        a, a_end = makeHTMLTags("A")
-        link_expr = a + SkipTo(a_end)("link_text") + a_end
-
-        for link in link_expr.searchString(text):
-            # attributes in the <A> tag (like "href" shown here) are
-            # also accessible as named results
-            print(link.link_text, '->', link.href)
-
-    prints::
-
-        pyparsing -> https://github.com/pyparsing/pyparsing/wiki
-    """
-    return _makeTags(tagStr, False)
-
-def makeXMLTags(tagStr):
-    """Helper to construct opening and closing tag expressions for XML,
-    given a tag name. Matches tags only in the given upper/lower case.
-
-    Example: similar to :class:`makeHTMLTags`
-    """
-    return _makeTags(tagStr, True)
-
-def withAttribute(*args, **attrDict):
-    """Helper to create a validating parse action to be used with start
-    tags created with :class:`makeXMLTags` or
-    :class:`makeHTMLTags`. Use ``withAttribute`` to qualify
-    a starting tag with a required attribute value, to avoid false
-    matches on common tags such as ``<TD>`` or ``<DIV>``.
-
-    Call ``withAttribute`` with a series of attribute names and
-    values. Specify the list of filter attributes names and values as:
-
-     - keyword arguments, as in ``(align="right")``, or
-     - as an explicit dict with ``**`` operator, when an attribute
-       name is also a Python reserved word, as in ``**{"class":"Customer", "align":"right"}``
-     - a list of name-value tuples, as in ``(("ns1:class", "Customer"), ("ns2:align", "right"))``
-
-    For attribute names with a namespace prefix, you must use the second
-    form.  Attribute names are matched insensitive to upper/lower case.
-
-    If just testing for ``class`` (with or without a namespace), use
-    :class:`withClass`.
-
-    To verify that the attribute exists, but without specifying a value,
-    pass ``withAttribute.ANY_VALUE`` as the value.
-
-    Example::
-
-        html = '''
-            <div>
-            Some text
-            <div type="grid">1 4 0 1 0</div>
-            <div type="graph">1,3 2,3 1,1</div>
-            <div>this has no type</div>
-            </div>
-
-        '''
-        div,div_end = makeHTMLTags("div")
-
-        # only match div tag having a type attribute with value "grid"
-        div_grid = div().setParseAction(withAttribute(type="grid"))
-        grid_expr = div_grid + SkipTo(div | div_end)("body")
-        for grid_header in grid_expr.searchString(html):
-            print(grid_header.body)
-
-        # construct a match with any div tag having a type attribute, regardless of the value
-        div_any_type = div().setParseAction(withAttribute(type=withAttribute.ANY_VALUE))
-        div_expr = div_any_type + SkipTo(div | div_end)("body")
-        for div_header in div_expr.searchString(html):
-            print(div_header.body)
-
-    prints::
-
-        1 4 0 1 0
-
-        1 4 0 1 0
-        1,3 2,3 1,1
-    """
-    if args:
-        attrs = args[:]
-    else:
-        attrs = attrDict.items()
-    attrs = [(k, v) for k, v in attrs]
-    def pa(s, l, tokens):
-        for attrName, attrValue in attrs:
-            if attrName not in tokens:
-                raise ParseException(s, l, "no matching attribute " + attrName)
-            if attrValue != withAttribute.ANY_VALUE and tokens[attrName] != attrValue:
-                raise ParseException(s, l, "attribute '%s' has value '%s', must be '%s'" %
-                                            (attrName, tokens[attrName], attrValue))
-    return pa
-withAttribute.ANY_VALUE = object()
-
-def withClass(classname, namespace=''):
-    """Simplified version of :class:`withAttribute` when
-    matching on a div class - made difficult because ``class`` is
-    a reserved word in Python.
-
-    Example::
-
-        html = '''
-            <div>
-            Some text
-            <div class="grid">1 4 0 1 0</div>
-            <div class="graph">1,3 2,3 1,1</div>
-            <div>this &lt;div&gt; has no class</div>
-            </div>
-
-        '''
-        div,div_end = makeHTMLTags("div")
-        div_grid = div().setParseAction(withClass("grid"))
-
-        grid_expr = div_grid + SkipTo(div | div_end)("body")
-        for grid_header in grid_expr.searchString(html):
-            print(grid_header.body)
-
-        div_any_type = div().setParseAction(withClass(withAttribute.ANY_VALUE))
-        div_expr = div_any_type + SkipTo(div | div_end)("body")
-        for div_header in div_expr.searchString(html):
-            print(div_header.body)
-
-    prints::
-
-        1 4 0 1 0
-
-        1 4 0 1 0
-        1,3 2,3 1,1
-    """
-    classattr = "%s:class" % namespace if namespace else "class"
-    return withAttribute(**{classattr: classname})
-
-opAssoc = SimpleNamespace()
-opAssoc.LEFT = object()
-opAssoc.RIGHT = object()
-
-def infixNotation(baseExpr, opList, lpar=Suppress('('), rpar=Suppress(')')):
-    """Helper method for constructing grammars of expressions made up of
-    operators working in a precedence hierarchy.  Operators may be unary
-    or binary, left- or right-associative.  Parse actions can also be
-    attached to operator expressions. The generated parser will also
-    recognize the use of parentheses to override operator precedences
-    (see example below).
-
-    Note: if you define a deep operator list, you may see performance
-    issues when using infixNotation. See
-    :class:`ParserElement.enablePackrat` for a mechanism to potentially
-    improve your parser performance.
-
-    Parameters:
-     - baseExpr - expression representing the most basic element for the
-       nested
-     - opList - list of tuples, one for each operator precedence level
-       in the expression grammar; each tuple is of the form ``(opExpr,
-       numTerms, rightLeftAssoc, parseAction)``, where:
-
-       - opExpr is the pyparsing expression for the operator; may also
-         be a string, which will be converted to a Literal; if numTerms
-         is 3, opExpr is a tuple of two expressions, for the two
-         operators separating the 3 terms
-       - numTerms is the number of terms for this operator (must be 1,
-         2, or 3)
-       - rightLeftAssoc is the indicator whether the operator is right
-         or left associative, using the pyparsing-defined constants
-         ``opAssoc.RIGHT`` and ``opAssoc.LEFT``.
-       - parseAction is the parse action to be associated with
-         expressions matching this operator expression (the parse action
-         tuple member may be omitted); if the parse action is passed
-         a tuple or list of functions, this is equivalent to calling
-         ``setParseAction(*fn)``
-         (:class:`ParserElement.setParseAction`)
-     - lpar - expression for matching left-parentheses
-       (default= ``Suppress('(')``)
-     - rpar - expression for matching right-parentheses
-       (default= ``Suppress(')')``)
-
-    Example::
-
-        # simple example of four-function arithmetic with ints and
-        # variable names
-        integer = pyparsing_common.signed_integer
-        varname = pyparsing_common.identifier
-
-        arith_expr = infixNotation(integer | varname,
-            [
-            ('-', 1, opAssoc.RIGHT),
-            (oneOf('* /'), 2, opAssoc.LEFT),
-            (oneOf('+ -'), 2, opAssoc.LEFT),
-            ])
-
-        arith_expr.runTests('''
-            5+3*6
-            (5+3)*6
-            -2--11
-            ''', fullDump=False)
-
-    prints::
-
-        5+3*6
-        [[5, '+', [3, '*', 6]]]
-
-        (5+3)*6
-        [[[5, '+', 3], '*', 6]]
-
-        -2--11
-        [[['-', 2], '-', ['-', 11]]]
-    """
-    # captive version of FollowedBy that does not do parse actions or capture results names
-    class _FB(FollowedBy):
-        def parseImpl(self, instring, loc, doActions=True):
-            self.expr.tryParse(instring, loc)
-            return loc, []
-
-    ret = Forward()
-    lastExpr = baseExpr | (lpar + ret + rpar)
-    for i, operDef in enumerate(opList):
-        opExpr, arity, rightLeftAssoc, pa = (operDef + (None, ))[:4]
-        termName = "%s term" % opExpr if arity < 3 else "%s%s term" % opExpr
-        if arity == 3:
-            if opExpr is None or len(opExpr) != 2:
-                raise ValueError(
-                    "if numterms=3, opExpr must be a tuple or list of two expressions")
-            opExpr1, opExpr2 = opExpr
-        thisExpr = Forward().setName(termName)
-        if rightLeftAssoc == opAssoc.LEFT:
-            if arity == 1:
-                matchExpr = _FB(lastExpr + opExpr) + Group(lastExpr + OneOrMore(opExpr))
-            elif arity == 2:
-                if opExpr is not None:
-                    matchExpr = _FB(lastExpr + opExpr + lastExpr) + Group(lastExpr + OneOrMore(opExpr + lastExpr))
-                else:
-                    matchExpr = _FB(lastExpr + lastExpr) + Group(lastExpr + OneOrMore(lastExpr))
-            elif arity == 3:
-                matchExpr = (_FB(lastExpr + opExpr1 + lastExpr + opExpr2 + lastExpr)
-                             + Group(lastExpr + OneOrMore(opExpr1 + lastExpr + opExpr2 + lastExpr)))
-            else:
-                raise ValueError("operator must be unary (1), binary (2), or ternary (3)")
-        elif rightLeftAssoc == opAssoc.RIGHT:
-            if arity == 1:
-                # try to avoid LR with this extra test
-                if not isinstance(opExpr, Optional):
-                    opExpr = Optional(opExpr)
-                matchExpr = _FB(opExpr.expr + thisExpr) + Group(opExpr + thisExpr)
-            elif arity == 2:
-                if opExpr is not None:
-                    matchExpr = _FB(lastExpr + opExpr + thisExpr) + Group(lastExpr + OneOrMore(opExpr + thisExpr))
-                else:
-                    matchExpr = _FB(lastExpr + thisExpr) + Group(lastExpr + OneOrMore(thisExpr))
-            elif arity == 3:
-                matchExpr = (_FB(lastExpr + opExpr1 + thisExpr + opExpr2 + thisExpr)
-                             + Group(lastExpr + opExpr1 + thisExpr + opExpr2 + thisExpr))
-            else:
-                raise ValueError("operator must be unary (1), binary (2), or ternary (3)")
-        else:
-            raise ValueError("operator must indicate right or left associativity")
-        if pa:
-            if isinstance(pa, (tuple, list)):
-                matchExpr.setParseAction(*pa)
-            else:
-                matchExpr.setParseAction(pa)
-        thisExpr <<= (matchExpr.setName(termName) | lastExpr)
-        lastExpr = thisExpr
-    ret <<= lastExpr
-    return ret
-
-operatorPrecedence = infixNotation
-"""(Deprecated) Former name of :class:`infixNotation`, will be
-dropped in a future release."""
-
-dblQuotedString = Combine(Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*') + '"').setName("string enclosed in double quotes")
-sglQuotedString = Combine(Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*") + "'").setName("string enclosed in single quotes")
-quotedString = Combine(Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*') + '"'
-                       | Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*") + "'").setName("quotedString using single or double quotes")
-unicodeString = Combine(_L('u') + quotedString.copy()).setName("unicode string literal")
-
-def nestedExpr(opener="(", closer=")", content=None, ignoreExpr=quotedString.copy()):
-    """Helper method for defining nested lists enclosed in opening and
-    closing delimiters ("(" and ")" are the default).
-
-    Parameters:
-     - opener - opening character for a nested list
-       (default= ``"("``); can also be a pyparsing expression
-     - closer - closing character for a nested list
-       (default= ``")"``); can also be a pyparsing expression
-     - content - expression for items within the nested lists
-       (default= ``None``)
-     - ignoreExpr - expression for ignoring opening and closing
-       delimiters (default= :class:`quotedString`)
-
-    If an expression is not provided for the content argument, the
-    nested expression will capture all whitespace-delimited content
-    between delimiters as a list of separate values.
-
-    Use the ``ignoreExpr`` argument to define expressions that may
-    contain opening or closing characters that should not be treated as
-    opening or closing characters for nesting, such as quotedString or
-    a comment expression.  Specify multiple expressions using an
-    :class:`Or` or :class:`MatchFirst`. The default is
-    :class:`quotedString`, but if no expressions are to be ignored, then
-    pass ``None`` for this argument.
-
-    Example::
-
-        data_type = oneOf("void int short long char float double")
-        decl_data_type = Combine(data_type + Optional(Word('*')))
-        ident = Word(alphas+'_', alphanums+'_')
-        number = pyparsing_common.number
-        arg = Group(decl_data_type + ident)
-        LPAR, RPAR = map(Suppress, "()")
-
-        code_body = nestedExpr('{', '}', ignoreExpr=(quotedString | cStyleComment))
-
-        c_function = (decl_data_type("type")
-                      + ident("name")
-                      + LPAR + Optional(delimitedList(arg), [])("args") + RPAR
-                      + code_body("body"))
-        c_function.ignore(cStyleComment)
-
-        source_code = '''
-            int is_odd(int x) {
-                return (x%2);
-            }
-
-            int dec_to_hex(char hchar) {
-                if (hchar >= '0' && hchar <= '9') {
-                    return (ord(hchar)-ord('0'));
-                } else {
-                    return (10+ord(hchar)-ord('A'));
-                }
-            }
-        '''
-        for func in c_function.searchString(source_code):
-            print("%(name)s (%(type)s) args: %(args)s" % func)
-
-
-    prints::
-
-        is_odd (int) args: [['int', 'x']]
-        dec_to_hex (int) args: [['char', 'hchar']]
-    """
-    if opener == closer:
-        raise ValueError("opening and closing strings cannot be the same")
-    if content is None:
-        if isinstance(opener, basestring) and isinstance(closer, basestring):
-            if len(opener) == 1 and len(closer) == 1:
-                if ignoreExpr is not None:
-                    content = (Combine(OneOrMore(~ignoreExpr
-                                                 + CharsNotIn(opener
-                                                              + closer
-                                                              + ParserElement.DEFAULT_WHITE_CHARS, exact=1)
-                                                 )
-                                       ).setParseAction(lambda t: t[0].strip()))
-                else:
-                    content = (empty.copy() + CharsNotIn(opener
-                                                         + closer
-                                                         + ParserElement.DEFAULT_WHITE_CHARS
-                                                         ).setParseAction(lambda t: t[0].strip()))
-            else:
-                if ignoreExpr is not None:
-                    content = (Combine(OneOrMore(~ignoreExpr
-                                                 + ~Literal(opener)
-                                                 + ~Literal(closer)
-                                                 + CharsNotIn(ParserElement.DEFAULT_WHITE_CHARS, exact=1))
-                                       ).setParseAction(lambda t: t[0].strip()))
-                else:
-                    content = (Combine(OneOrMore(~Literal(opener)
-                                                 + ~Literal(closer)
-                                                 + CharsNotIn(ParserElement.DEFAULT_WHITE_CHARS, exact=1))
-                                       ).setParseAction(lambda t: t[0].strip()))
-        else:
-            raise ValueError("opening and closing arguments must be strings if no content expression is given")
-    ret = Forward()
-    if ignoreExpr is not None:
-        ret <<= Group(Suppress(opener) + ZeroOrMore(ignoreExpr | ret | content) + Suppress(closer))
-    else:
-        ret <<= Group(Suppress(opener) + ZeroOrMore(ret | content)  + Suppress(closer))
-    ret.setName('nested %s%s expression' % (opener, closer))
-    return ret
-
-def indentedBlock(blockStatementExpr, indentStack, indent=True):
-    """Helper method for defining space-delimited indentation blocks,
-    such as those used to define block statements in Python source code.
-
-    Parameters:
-
-     - blockStatementExpr - expression defining syntax of statement that
-       is repeated within the indented block
-     - indentStack - list created by caller to manage indentation stack
-       (multiple statementWithIndentedBlock expressions within a single
-       grammar should share a common indentStack)
-     - indent - boolean indicating whether block must be indented beyond
-       the current level; set to False for block of left-most
-       statements (default= ``True``)
-
-    A valid block must contain at least one ``blockStatement``.
-
-    Example::
-
-        data = '''
-        def A(z):
-          A1
-          B = 100
-          G = A2
-          A2
-          A3
-        B
-        def BB(a,b,c):
-          BB1
-          def BBA():
-            bba1
-            bba2
-            bba3
-        C
-        D
-        def spam(x,y):
-             def eggs(z):
-                 pass
-        '''
-
-
-        indentStack = [1]
-        stmt = Forward()
-
-        identifier = Word(alphas, alphanums)
-        funcDecl = ("def" + identifier + Group("(" + Optional(delimitedList(identifier)) + ")") + ":")
-        func_body = indentedBlock(stmt, indentStack)
-        funcDef = Group(funcDecl + func_body)
-
-        rvalue = Forward()
-        funcCall = Group(identifier + "(" + Optional(delimitedList(rvalue)) + ")")
-        rvalue << (funcCall | identifier | Word(nums))
-        assignment = Group(identifier + "=" + rvalue)
-        stmt << (funcDef | assignment | identifier)
-
-        module_body = OneOrMore(stmt)
-
-        parseTree = module_body.parseString(data)
-        parseTree.pprint()
-
-    prints::
-
-        [['def',
-          'A',
-          ['(', 'z', ')'],
-          ':',
-          [['A1'], [['B', '=', '100']], [['G', '=', 'A2']], ['A2'], ['A3']]],
-         'B',
-         ['def',
-          'BB',
-          ['(', 'a', 'b', 'c', ')'],
-          ':',
-          [['BB1'], [['def', 'BBA', ['(', ')'], ':', [['bba1'], ['bba2'], ['bba3']]]]]],
-         'C',
-         'D',
-         ['def',
-          'spam',
-          ['(', 'x', 'y', ')'],
-          ':',
-          [[['def', 'eggs', ['(', 'z', ')'], ':', [['pass']]]]]]]
-    """
-    backup_stack = indentStack[:]
-
-    def reset_stack():
-        indentStack[:] = backup_stack
-
-    def checkPeerIndent(s, l, t):
-        if l >= len(s): return
-        curCol = col(l, s)
-        if curCol != indentStack[-1]:
-            if curCol > indentStack[-1]:
-                raise ParseException(s, l, "illegal nesting")
-            raise ParseException(s, l, "not a peer entry")
-
-    def checkSubIndent(s, l, t):
-        curCol = col(l, s)
-        if curCol > indentStack[-1]:
-            indentStack.append(curCol)
-        else:
-            raise ParseException(s, l, "not a subentry")
-
-    def checkUnindent(s, l, t):
-        if l >= len(s): return
-        curCol = col(l, s)
-        if not(indentStack and curCol in indentStack):
-            raise ParseException(s, l, "not an unindent")
-        if curCol < indentStack[-1]:
-            indentStack.pop()
-
-    NL = OneOrMore(LineEnd().setWhitespaceChars("\t ").suppress(), stopOn=StringEnd())
-    INDENT = (Empty() + Empty().setParseAction(checkSubIndent)).setName('INDENT')
-    PEER   = Empty().setParseAction(checkPeerIndent).setName('')
-    UNDENT = Empty().setParseAction(checkUnindent).setName('UNINDENT')
-    if indent:
-        smExpr = Group(Optional(NL)
-                       + INDENT
-                       + OneOrMore(PEER + Group(blockStatementExpr) + Optional(NL), stopOn=StringEnd())
-                       + UNDENT)
-    else:
-        smExpr = Group(Optional(NL)
-                       + OneOrMore(PEER + Group(blockStatementExpr) + Optional(NL), stopOn=StringEnd())
-                       + UNDENT)
-    smExpr.setFailAction(lambda a, b, c, d: reset_stack())
-    blockStatementExpr.ignore(_bslash + LineEnd())
-    return smExpr.setName('indented block')
-
-alphas8bit = srange(r"[\0xc0-\0xd6\0xd8-\0xf6\0xf8-\0xff]")
-punc8bit = srange(r"[\0xa1-\0xbf\0xd7\0xf7]")
-
-anyOpenTag, anyCloseTag = makeHTMLTags(Word(alphas, alphanums + "_:").setName('any tag'))
-_htmlEntityMap = dict(zip("gt lt amp nbsp quot apos".split(), '><& "\''))
-commonHTMLEntity = Regex('&(?P<entity>' + '|'.join(_htmlEntityMap.keys()) +");").setName("common HTML entity")
-def replaceHTMLEntity(t):
-    """Helper parser action to replace common HTML entities with their special characters"""
-    return _htmlEntityMap.get(t.entity)
-
-# it's easy to get these comment structures wrong - they're very common, so may as well make them available
-cStyleComment = Combine(Regex(r"/\*(?:[^*]|\*(?!/))*") + '*/').setName("C style comment")
-"Comment of the form ``/* ... */``"
-
-htmlComment = Regex(r"<!--[\s\S]*?-->").setName("HTML comment")
-"Comment of the form ``<!-- ... -->``"
-
-restOfLine = Regex(r".*").leaveWhitespace().setName("rest of line")
-dblSlashComment = Regex(r"//(?:\\\n|[^\n])*").setName("// comment")
-"Comment of the form ``// ... (to end of line)``"
-
-cppStyleComment = Combine(Regex(r"/\*(?:[^*]|\*(?!/))*") + '*/' | dblSlashComment).setName("C++ style comment")
-"Comment of either form :class:`cStyleComment` or :class:`dblSlashComment`"
-
-javaStyleComment = cppStyleComment
-"Same as :class:`cppStyleComment`"
-
-pythonStyleComment = Regex(r"#.*").setName("Python style comment")
-"Comment of the form ``# ... (to end of line)``"
-
-_commasepitem = Combine(OneOrMore(Word(printables, excludeChars=',')
-                                  + Optional(Word(" \t")
-                                             + ~Literal(",") + ~LineEnd()))).streamline().setName("commaItem")
-commaSeparatedList = delimitedList(Optional(quotedString.copy() | _commasepitem, default="")).setName("commaSeparatedList")
-"""(Deprecated) Predefined expression of 1 or more printable words or
-quoted strings, separated by commas.
-
-This expression is deprecated in favor of :class:`pyparsing_common.comma_separated_list`.
-"""
-
-# some other useful expressions - using lower-case class name since we are really using this as a namespace
-class pyparsing_common:
-    """Here are some common low-level expressions that may be useful in
-    jump-starting parser development:
-
-     - numeric forms (:class:`integers<integer>`, :class:`reals<real>`,
-       :class:`scientific notation<sci_real>`)
-     - common :class:`programming identifiers<identifier>`
-     - network addresses (:class:`MAC<mac_address>`,
-       :class:`IPv4<ipv4_address>`, :class:`IPv6<ipv6_address>`)
-     - ISO8601 :class:`dates<iso8601_date>` and
-       :class:`datetime<iso8601_datetime>`
-     - :class:`UUID<uuid>`
-     - :class:`comma-separated list<comma_separated_list>`
-
-    Parse actions:
-
-     - :class:`convertToInteger`
-     - :class:`convertToFloat`
-     - :class:`convertToDate`
-     - :class:`convertToDatetime`
-     - :class:`stripHTMLTags`
-     - :class:`upcaseTokens`
-     - :class:`downcaseTokens`
-
-    Example::
-
-        pyparsing_common.number.runTests('''
-            # any int or real number, returned as the appropriate type
-            100
-            -100
-            +100
-            3.14159
-            6.02e23
-            1e-12
-            ''')
-
-        pyparsing_common.fnumber.runTests('''
-            # any int or real number, returned as float
-            100
-            -100
-            +100
-            3.14159
-            6.02e23
-            1e-12
-            ''')
-
-        pyparsing_common.hex_integer.runTests('''
-            # hex numbers
-            100
-            FF
-            ''')
-
-        pyparsing_common.fraction.runTests('''
-            # fractions
-            1/2
-            -3/4
-            ''')
-
-        pyparsing_common.mixed_integer.runTests('''
-            # mixed fractions
-            1
-            1/2
-            -3/4
-            1-3/4
-            ''')
-
-        import uuid
-        pyparsing_common.uuid.setParseAction(tokenMap(uuid.UUID))
-        pyparsing_common.uuid.runTests('''
-            # uuid
-            12345678-1234-5678-1234-567812345678
-            ''')
-
-    prints::
-
-        # any int or real number, returned as the appropriate type
-        100
-        [100]
-
-        -100
-        [-100]
-
-        +100
-        [100]
-
-        3.14159
-        [3.14159]
-
-        6.02e23
-        [6.02e+23]
-
-        1e-12
-        [1e-12]
-
-        # any int or real number, returned as float
-        100
-        [100.0]
-
-        -100
-        [-100.0]
-
-        +100
-        [100.0]
-
-        3.14159
-        [3.14159]
-
-        6.02e23
-        [6.02e+23]
-
-        1e-12
-        [1e-12]
-
-        # hex numbers
-        100
-        [256]
-
-        FF
-        [255]
-
-        # fractions
-        1/2
-        [0.5]
-
-        -3/4
-        [-0.75]
-
-        # mixed fractions
-        1
-        [1]
-
-        1/2
-        [0.5]
-
-        -3/4
-        [-0.75]
-
-        1-3/4
-        [1.75]
-
-        # uuid
-        12345678-1234-5678-1234-567812345678
-        [UUID('12345678-1234-5678-1234-567812345678')]
-    """
-
-    convertToInteger = tokenMap(int)
-    """
-    Parse action for converting parsed integers to Python int
-    """
-
-    convertToFloat = tokenMap(float)
-    """
-    Parse action for converting parsed numbers to Python float
-    """
-
-    integer = Word(nums).setName("integer").setParseAction(convertToInteger)
-    """expression that parses an unsigned integer, returns an int"""
-
-    hex_integer = Word(hexnums).setName("hex integer").setParseAction(tokenMap(int, 16))
-    """expression that parses a hexadecimal integer, returns an int"""
-
-    signed_integer = Regex(r'[+-]?\d+').setName("signed integer").setParseAction(convertToInteger)
-    """expression that parses an integer with optional leading sign, returns an int"""
-
-    fraction = (signed_integer().setParseAction(convertToFloat) + '/' + signed_integer().setParseAction(convertToFloat)).setName("fraction")
-    """fractional expression of an integer divided by an integer, returns a float"""
-    fraction.addParseAction(lambda t: t[0]/t[-1])
-
-    mixed_integer = (fraction | signed_integer + Optional(Optional('-').suppress() + fraction)).setName("fraction or mixed integer-fraction")
-    """mixed integer of the form 'integer - fraction', with optional leading integer, returns float"""
-    mixed_integer.addParseAction(sum)
-
-    real = Regex(r'[+-]?(?:\d+\.\d*|\.\d+)').setName("real number").setParseAction(convertToFloat)
-    """expression that parses a floating point number and returns a float"""
-
-    sci_real = Regex(r'[+-]?(?:\d+(?:[eE][+-]?\d+)|(?:\d+\.\d*|\.\d+)(?:[eE][+-]?\d+)?)').setName("real number with scientific notation").setParseAction(convertToFloat)
-    """expression that parses a floating point number with optional
-    scientific notation and returns a float"""
-
-    # streamlining this expression makes the docs nicer-looking
-    number = (sci_real | real | signed_integer).streamline()
-    """any numeric expression, returns the corresponding Python type"""
-
-    fnumber = Regex(r'[+-]?\d+\.?\d*([eE][+-]?\d+)?').setName("fnumber").setParseAction(convertToFloat)
-    """any int or real number, returned as float"""
-
-    identifier = Word(alphas + '_', alphanums + '_').setName("identifier")
-    """typical code identifier (leading alpha or '_', followed by 0 or more alphas, nums, or '_')"""
-
-    ipv4_address = Regex(r'(25[0-5]|2[0-4][0-9]|1?[0-9]{1,2})(\.(25[0-5]|2[0-4][0-9]|1?[0-9]{1,2})){3}').setName("IPv4 address")
-    "IPv4 address (``0.0.0.0 - 255.255.255.255``)"
-
-    _ipv6_part = Regex(r'[0-9a-fA-F]{1,4}').setName("hex_integer")
-    _full_ipv6_address = (_ipv6_part + (':' + _ipv6_part) * 7).setName("full IPv6 address")
-    _short_ipv6_address = (Optional(_ipv6_part + (':' + _ipv6_part) * (0, 6))
-                           + "::"
-                           + Optional(_ipv6_part + (':' + _ipv6_part) * (0, 6))
-                           ).setName("short IPv6 address")
-    _short_ipv6_address.addCondition(lambda t: sum(1 for tt in t if pyparsing_common._ipv6_part.matches(tt)) < 8)
-    _mixed_ipv6_address = ("::ffff:" + ipv4_address).setName("mixed IPv6 address")
-    ipv6_address = Combine((_full_ipv6_address | _mixed_ipv6_address | _short_ipv6_address).setName("IPv6 address")).setName("IPv6 address")
-    "IPv6 address (long, short, or mixed form)"
-
-    mac_address = Regex(r'[0-9a-fA-F]{2}([:.-])[0-9a-fA-F]{2}(?:\1[0-9a-fA-F]{2}){4}').setName("MAC address")
-    "MAC address xx:xx:xx:xx:xx (may also have '-' or '.' delimiters)"
-
-    @staticmethod
-    def convertToDate(fmt="%Y-%m-%d"):
-        """
-        Helper to create a parse action for converting parsed date string to Python datetime.date
-
-        Params -
-         - fmt - format to be passed to datetime.strptime (default= ``"%Y-%m-%d"``)
-
-        Example::
-
-            date_expr = pyparsing_common.iso8601_date.copy()
-            date_expr.setParseAction(pyparsing_common.convertToDate())
-            print(date_expr.parseString("1999-12-31"))
-
-        prints::
-
-            [datetime.date(1999, 12, 31)]
-        """
-        def cvt_fn(s, l, t):
-            try:
-                return datetime.strptime(t[0], fmt).date()
-            except ValueError as ve:
-                raise ParseException(s, l, str(ve))
-        return cvt_fn
-
-    @staticmethod
-    def convertToDatetime(fmt="%Y-%m-%dT%H:%M:%S.%f"):
-        """Helper to create a parse action for converting parsed
-        datetime string to Python datetime.datetime
-
-        Params -
-         - fmt - format to be passed to datetime.strptime (default= ``"%Y-%m-%dT%H:%M:%S.%f"``)
-
-        Example::
-
-            dt_expr = pyparsing_common.iso8601_datetime.copy()
-            dt_expr.setParseAction(pyparsing_common.convertToDatetime())
-            print(dt_expr.parseString("1999-12-31T23:59:59.999"))
-
-        prints::
-
-            [datetime.datetime(1999, 12, 31, 23, 59, 59, 999000)]
-        """
-        def cvt_fn(s, l, t):
-            try:
-                return datetime.strptime(t[0], fmt)
-            except ValueError as ve:
-                raise ParseException(s, l, str(ve))
-        return cvt_fn
-
-    iso8601_date = Regex(r'(?P<year>\d{4})(?:-(?P<month>\d\d)(?:-(?P<day>\d\d))?)?').setName("ISO8601 date")
-    "ISO8601 date (``yyyy-mm-dd``)"
-
-    iso8601_datetime = Regex(r'(?P<year>\d{4})-(?P<month>\d\d)-(?P<day>\d\d)[T ](?P<hour>\d\d):(?P<minute>\d\d)(:(?P<second>\d\d(\.\d*)?)?)?(?P<tz>Z|[+-]\d\d:?\d\d)?').setName("ISO8601 datetime")
-    "ISO8601 datetime (``yyyy-mm-ddThh:mm:ss.s(Z|+-00:00)``) - trailing seconds, milliseconds, and timezone optional; accepts separating ``'T'`` or ``' '``"
-
-    uuid = Regex(r'[0-9a-fA-F]{8}(-[0-9a-fA-F]{4}){3}-[0-9a-fA-F]{12}').setName("UUID")
-    "UUID (``xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx``)"
-
-    _html_stripper = anyOpenTag.suppress() | anyCloseTag.suppress()
-    @staticmethod
-    def stripHTMLTags(s, l, tokens):
-        """Parse action to remove HTML tags from web page HTML source
-
-        Example::
-
-            # strip HTML links from normal text
-            text = '<td>More info at the <a href="https://github.com/pyparsing/pyparsing/wiki">pyparsing</a> wiki page</td>'
-            td, td_end = makeHTMLTags("TD")
-            table_text = td + SkipTo(td_end).setParseAction(pyparsing_common.stripHTMLTags)("body") + td_end
-            print(table_text.parseString(text).body)
-
-        Prints::
-
-            More info at the pyparsing wiki page
-        """
-        return pyparsing_common._html_stripper.transformString(tokens[0])
-
-    _commasepitem = Combine(OneOrMore(~Literal(",")
-                                      + ~LineEnd()
-                                      + Word(printables, excludeChars=',')
-                                      + Optional(White(" \t")))).streamline().setName("commaItem")
-    comma_separated_list = delimitedList(Optional(quotedString.copy()
-                                                  | _commasepitem, default='')
-                                         ).setName("comma separated list")
-    """Predefined expression of 1 or more printable words or quoted strings, separated by commas."""
-
-    upcaseTokens = staticmethod(tokenMap(lambda t: _ustr(t).upper()))
-    """Parse action to convert tokens to upper case."""
-
-    downcaseTokens = staticmethod(tokenMap(lambda t: _ustr(t).lower()))
-    """Parse action to convert tokens to lower case."""
-
-
-class _lazyclassproperty(object):
-    def __init__(self, fn):
-        self.fn = fn
-        self.__doc__ = fn.__doc__
-        self.__name__ = fn.__name__
-
-    def __get__(self, obj, cls):
-        if cls is None:
-            cls = type(obj)
-        if not hasattr(cls, '_intern') or any(cls._intern is getattr(superclass, '_intern', [])
-                                              for superclass in cls.__mro__[1:]):
-            cls._intern = {}
-        attrname = self.fn.__name__
-        if attrname not in cls._intern:
-            cls._intern[attrname] = self.fn(cls)
-        return cls._intern[attrname]
-
-
-class unicode_set(object):
-    """
-    A set of Unicode characters, for language-specific strings for
-    ``alphas``, ``nums``, ``alphanums``, and ``printables``.
-    A unicode_set is defined by a list of ranges in the Unicode character
-    set, in a class attribute ``_ranges``, such as::
-
-        _ranges = [(0x0020, 0x007e), (0x00a0, 0x00ff),]
-
-    A unicode set can also be defined using multiple inheritance of other unicode sets::
-
-        class CJK(Chinese, Japanese, Korean):
-            pass
-    """
-    _ranges = []
-
-    @classmethod
-    def _get_chars_for_ranges(cls):
-        ret = []
-        for cc in cls.__mro__:
-            if cc is unicode_set:
-                break
-            for rr in cc._ranges:
-                ret.extend(range(rr[0], rr[-1] + 1))
-        return [unichr(c) for c in sorted(set(ret))]
-
-    @_lazyclassproperty
-    def printables(cls):
-        "all non-whitespace characters in this range"
-        return u''.join(filterfalse(unicode.isspace, cls._get_chars_for_ranges()))
-
-    @_lazyclassproperty
-    def alphas(cls):
-        "all alphabetic characters in this range"
-        return u''.join(filter(unicode.isalpha, cls._get_chars_for_ranges()))
-
-    @_lazyclassproperty
-    def nums(cls):
-        "all numeric digit characters in this range"
-        return u''.join(filter(unicode.isdigit, cls._get_chars_for_ranges()))
-
-    @_lazyclassproperty
-    def alphanums(cls):
-        "all alphanumeric characters in this range"
-        return cls.alphas + cls.nums
-
-
-class pyparsing_unicode(unicode_set):
-    """
-    A namespace class for defining common language unicode_sets.
-    """
-    _ranges = [(32, sys.maxunicode)]
-
-    class Latin1(unicode_set):
-        "Unicode set for Latin-1 Unicode Character Range"
-        _ranges = [(0x0020, 0x007e), (0x00a0, 0x00ff),]
-
-    class LatinA(unicode_set):
-        "Unicode set for Latin-A Unicode Character Range"
-        _ranges = [(0x0100, 0x017f),]
-
-    class LatinB(unicode_set):
-        "Unicode set for Latin-B Unicode Character Range"
-        _ranges = [(0x0180, 0x024f),]
-
-    class Greek(unicode_set):
-        "Unicode set for Greek Unicode Character Ranges"
-        _ranges = [
-            (0x0370, 0x03ff), (0x1f00, 0x1f15), (0x1f18, 0x1f1d), (0x1f20, 0x1f45), (0x1f48, 0x1f4d),
-            (0x1f50, 0x1f57), (0x1f59,), (0x1f5b,), (0x1f5d,), (0x1f5f, 0x1f7d), (0x1f80, 0x1fb4), (0x1fb6, 0x1fc4),
-            (0x1fc6, 0x1fd3), (0x1fd6, 0x1fdb), (0x1fdd, 0x1fef), (0x1ff2, 0x1ff4), (0x1ff6, 0x1ffe),
-        ]
-
-    class Cyrillic(unicode_set):
-        "Unicode set for Cyrillic Unicode Character Range"
-        _ranges = [(0x0400, 0x04ff)]
-
-    class Chinese(unicode_set):
-        "Unicode set for Chinese Unicode Character Range"
-        _ranges = [(0x4e00, 0x9fff), (0x3000, 0x303f),]
-
-    class Japanese(unicode_set):
-        "Unicode set for Japanese Unicode Character Range, combining Kanji, Hiragana, and Katakana ranges"
-        _ranges = []
-
-        class Kanji(unicode_set):
-            "Unicode set for Kanji Unicode Character Range"
-            _ranges = [(0x4E00, 0x9Fbf), (0x3000, 0x303f),]
-
-        class Hiragana(unicode_set):
-            "Unicode set for Hiragana Unicode Character Range"
-            _ranges = [(0x3040, 0x309f),]
-
-        class Katakana(unicode_set):
-            "Unicode set for Katakana  Unicode Character Range"
-            _ranges = [(0x30a0, 0x30ff),]
-
-    class Korean(unicode_set):
-        "Unicode set for Korean Unicode Character Range"
-        _ranges = [(0xac00, 0xd7af), (0x1100, 0x11ff), (0x3130, 0x318f), (0xa960, 0xa97f), (0xd7b0, 0xd7ff), (0x3000, 0x303f),]
-
-    class CJK(Chinese, Japanese, Korean):
-        "Unicode set for combined Chinese, Japanese, and Korean (CJK) Unicode Character Range"
-        pass
-
-    class Thai(unicode_set):
-        "Unicode set for Thai Unicode Character Range"
-        _ranges = [(0x0e01, 0x0e3a), (0x0e3f, 0x0e5b),]
-
-    class Arabic(unicode_set):
-        "Unicode set for Arabic Unicode Character Range"
-        _ranges = [(0x0600, 0x061b), (0x061e, 0x06ff), (0x0700, 0x077f),]
-
-    class Hebrew(unicode_set):
-        "Unicode set for Hebrew Unicode Character Range"
-        _ranges = [(0x0590, 0x05ff),]
-
-    class Devanagari(unicode_set):
-        "Unicode set for Devanagari Unicode Character Range"
-        _ranges = [(0x0900, 0x097f), (0xa8e0, 0xa8ff)]
-
-pyparsing_unicode.Japanese._ranges = (pyparsing_unicode.Japanese.Kanji._ranges
-                                      + pyparsing_unicode.Japanese.Hiragana._ranges
-                                      + pyparsing_unicode.Japanese.Katakana._ranges)
-
-# define ranges in language character sets
-if PY_3:
-    setattr(pyparsing_unicode, u"العربية", pyparsing_unicode.Arabic)
-    setattr(pyparsing_unicode, u"中文", pyparsing_unicode.Chinese)
-    setattr(pyparsing_unicode, u"кириллица", pyparsing_unicode.Cyrillic)
-    setattr(pyparsing_unicode, u"Ελληνικά", pyparsing_unicode.Greek)
-    setattr(pyparsing_unicode, u"עִברִית", pyparsing_unicode.Hebrew)
-    setattr(pyparsing_unicode, u"日本語", pyparsing_unicode.Japanese)
-    setattr(pyparsing_unicode.Japanese, u"漢字", pyparsing_unicode.Japanese.Kanji)
-    setattr(pyparsing_unicode.Japanese, u"カタカナ", pyparsing_unicode.Japanese.Katakana)
-    setattr(pyparsing_unicode.Japanese, u"ひらがな", pyparsing_unicode.Japanese.Hiragana)
-    setattr(pyparsing_unicode, u"한국어", pyparsing_unicode.Korean)
-    setattr(pyparsing_unicode, u"ไทย", pyparsing_unicode.Thai)
-    setattr(pyparsing_unicode, u"देवनागरी", pyparsing_unicode.Devanagari)
-
-
-class pyparsing_test:
-    """
-    namespace class for classes useful in writing unit tests
-    """
-
-    class reset_pyparsing_context:
-        """
-        Context manager to be used when writing unit tests that modify pyparsing config values:
-         - packrat parsing
-         - default whitespace characters.
-         - default keyword characters
-         - literal string auto-conversion class
-         - __diag__ settings
-
-        Example:
-            with reset_pyparsing_context():
-                # test that literals used to construct a grammar are automatically suppressed
-                ParserElement.inlineLiteralsUsing(Suppress)
-
-                term = Word(alphas) | Word(nums)
-                group = Group('(' + term[...] + ')')
-
-                # assert that the '()' characters are not included in the parsed tokens
-                self.assertParseAndCheckLisst(group, "(abc 123 def)", ['abc', '123', 'def'])
-
-            # after exiting context manager, literals are converted to Literal expressions again
-        """
-
-        def __init__(self):
-            self._save_context = {}
-
-        def save(self):
-            self._save_context["default_whitespace"] = ParserElement.DEFAULT_WHITE_CHARS
-            self._save_context["default_keyword_chars"] = Keyword.DEFAULT_KEYWORD_CHARS
-            self._save_context[
-                "literal_string_class"
-            ] = ParserElement._literalStringClass
-            self._save_context["packrat_enabled"] = ParserElement._packratEnabled
-            self._save_context["packrat_parse"] = ParserElement._parse
-            self._save_context["__diag__"] = {
-                name: getattr(__diag__, name) for name in __diag__._all_names
-            }
-            self._save_context["__compat__"] = {
-                "collect_all_And_tokens": __compat__.collect_all_And_tokens
-            }
-            return self
-
-        def restore(self):
-            # reset pyparsing global state
-            if (
-                ParserElement.DEFAULT_WHITE_CHARS
-                != self._save_context["default_whitespace"]
-            ):
-                ParserElement.setDefaultWhitespaceChars(
-                    self._save_context["default_whitespace"]
-                )
-            Keyword.DEFAULT_KEYWORD_CHARS = self._save_context["default_keyword_chars"]
-            ParserElement.inlineLiteralsUsing(
-                self._save_context["literal_string_class"]
-            )
-            for name, value in self._save_context["__diag__"].items():
-                setattr(__diag__, name, value)
-            ParserElement._packratEnabled = self._save_context["packrat_enabled"]
-            ParserElement._parse = self._save_context["packrat_parse"]
-            __compat__.collect_all_And_tokens = self._save_context["__compat__"]
-
-        def __enter__(self):
-            return self.save()
-
-        def __exit__(self, *args):
-            return self.restore()
-
-    class TestParseResultsAsserts:
-        """
-        A mixin class to add parse results assertion methods to normal unittest.TestCase classes.
-        """
-        def assertParseResultsEquals(
-            self, result, expected_list=None, expected_dict=None, msg=None
-        ):
-            """
-            Unit test assertion to compare a ParseResults object with an optional expected_list,
-            and compare any defined results names with an optional expected_dict.
-            """
-            if expected_list is not None:
-                self.assertEqual(expected_list, result.asList(), msg=msg)
-            if expected_dict is not None:
-                self.assertEqual(expected_dict, result.asDict(), msg=msg)
-
-        def assertParseAndCheckList(
-            self, expr, test_string, expected_list, msg=None, verbose=True
-        ):
-            """
-            Convenience wrapper assert to test a parser element and input string, and assert that
-            the resulting ParseResults.asList() is equal to the expected_list.
-            """
-            result = expr.parseString(test_string, parseAll=True)
-            if verbose:
-                print(result.dump())
-            self.assertParseResultsEquals(result, expected_list=expected_list, msg=msg)
-
-        def assertParseAndCheckDict(
-            self, expr, test_string, expected_dict, msg=None, verbose=True
-        ):
-            """
-            Convenience wrapper assert to test a parser element and input string, and assert that
-            the resulting ParseResults.asDict() is equal to the expected_dict.
-            """
-            result = expr.parseString(test_string, parseAll=True)
-            if verbose:
-                print(result.dump())
-            self.assertParseResultsEquals(result, expected_dict=expected_dict, msg=msg)
-
-        def assertRunTestResults(
-            self, run_tests_report, expected_parse_results=None, msg=None
-        ):
-            """
-            Unit test assertion to evaluate output of ParserElement.runTests(). If a list of
-            list-dict tuples is given as the expected_parse_results argument, then these are zipped
-            with the report tuples returned by runTests and evaluated using assertParseResultsEquals.
-            Finally, asserts that the overall runTests() success value is True.
-
-            :param run_tests_report: tuple(bool, [tuple(str, ParseResults or Exception)]) returned from runTests
-            :param expected_parse_results (optional): [tuple(str, list, dict, Exception)]
-            """
-            run_test_success, run_test_results = run_tests_report
-
-            if expected_parse_results is not None:
-                merged = [
-                    (rpt[0], rpt[1], expected)
-                    for rpt, expected in zip(run_test_results, expected_parse_results)
-                ]
-                for test_string, result, expected in merged:
-                    # expected should be a tuple containing a list and/or a dict or an exception,
-                    # and optional failure message string
-                    # an empty tuple will skip any result validation
-                    fail_msg = next(
-                        (exp for exp in expected if isinstance(exp, str)), None
-                    )
-                    expected_exception = next(
-                        (
-                            exp
-                            for exp in expected
-                            if isinstance(exp, type) and issubclass(exp, Exception)
-                        ),
-                        None,
-                    )
-                    if expected_exception is not None:
-                        with self.assertRaises(
-                            expected_exception=expected_exception, msg=fail_msg or msg
-                        ):
-                            if isinstance(result, Exception):
-                                raise result
-                    else:
-                        expected_list = next(
-                            (exp for exp in expected if isinstance(exp, list)), None
-                        )
-                        expected_dict = next(
-                            (exp for exp in expected if isinstance(exp, dict)), None
-                        )
-                        if (expected_list, expected_dict) != (None, None):
-                            self.assertParseResultsEquals(
-                                result,
-                                expected_list=expected_list,
-                                expected_dict=expected_dict,
-                                msg=fail_msg or msg,
-                            )
-                        else:
-                            # warning here maybe?
-                            print("no validation for {!r}".format(test_string))
-
-            # do this last, in case some specific test results can be reported instead
-            self.assertTrue(
-                run_test_success, msg=msg if msg is not None else "failed runTests"
-            )
-
-        @contextmanager
-        def assertRaisesParseException(self, exc_type=ParseException, msg=None):
-            with self.assertRaises(exc_type, msg=msg):
-                yield
-
-
-if __name__ == "__main__":
-
-    selectToken    = CaselessLiteral("select")
-    fromToken      = CaselessLiteral("from")
-
-    ident          = Word(alphas, alphanums + "_$")
-
-    columnName     = delimitedList(ident, ".", combine=True).setParseAction(upcaseTokens)
-    columnNameList = Group(delimitedList(columnName)).setName("columns")
-    columnSpec     = ('*' | columnNameList)
-
-    tableName      = delimitedList(ident, ".", combine=True).setParseAction(upcaseTokens)
-    tableNameList  = Group(delimitedList(tableName)).setName("tables")
-
-    simpleSQL      = selectToken("command") + columnSpec("columns") + fromToken + tableNameList("tables")
-
-    # demo runTests method, including embedded comments in test string
-    simpleSQL.runTests("""
-        # '*' as column list and dotted table name
-        select * from SYS.XYZZY
-
-        # caseless match on "SELECT", and casts back to "select"
-        SELECT * from XYZZY, ABC
-
-        # list of column names, and mixed case SELECT keyword
-        Select AA,BB,CC from Sys.dual
-
-        # multiple tables
-        Select A, B, C from Sys.dual, Table2
-
-        # invalid SELECT keyword - should fail
-        Xelect A, B, C from Sys.dual
-
-        # incomplete command - should fail
-        Select
-
-        # invalid column name - should fail
-        Select ^^^ frox Sys.dual
-
-        """)
-
-    pyparsing_common.number.runTests("""
-        100
-        -100
-        +100
-        3.14159
-        6.02e23
-        1e-12
-        """)
-
-    # any int or real number, returned as float
-    pyparsing_common.fnumber.runTests("""
-        100
-        -100
-        +100
-        3.14159
-        6.02e23
-        1e-12
-        """)
-
-    pyparsing_common.hex_integer.runTests("""
-        100
-        FF
-        """)
-
-    import uuid
-    pyparsing_common.uuid.setParseAction(tokenMap(uuid.UUID))
-    pyparsing_common.uuid.runTests("""
-        12345678-1234-5678-1234-567812345678
-        """)
diff --git a/pyproject.toml b/pyproject.toml
index ac4b75d..1d0cb3f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,6 +20,6 @@ exclude = '''
 [tool.vendy]
 target = 'pip_api'
 packages = [
-    "packaging==21.0",
-    "pyparsing==2.4.7",
+    "packaging==23.2",
+    "packaging_legacy==23.0.post0",
 ]
diff --git a/setup.py b/setup.py
index 022dd7b..e838556 100644
--- a/setup.py
+++ b/setup.py
@@ -27,5 +27,5 @@
     python_requires=">=3.7",
     url="http://github.com/di/pip-api",
     summary="An unofficial, importable pip API",
-    version="0.0.30",
+    version="0.0.31",
 )