gh-127648: Improve Python startup time by ~12%

Author: mdboom

Lib/io.py

@@ -53,7 +53,6 @@
 import _io
 import abc
 
-from _collections_abc import _check_methods
 from _io import (DEFAULT_BUFFER_SIZE, BlockingIOError, UnsupportedOperation,
                  open, open_code, FileIO, BytesIO, StringIO, BufferedReader,
                  BufferedWriter, BufferedRWPair, BufferedRandom,
@@ -126,6 +125,7 @@ def read(self, size=..., /):
     @classmethod
     def __subclasshook__(cls, C):
         if cls is Reader:
+            from _collections_abc import _check_methods
             return _check_methods(C, "read")
         return NotImplemented
 
@@ -147,6 +147,7 @@ def write(self, data, /):
     @classmethod
     def __subclasshook__(cls, C):
         if cls is Writer:
+            from _collections_abc import _check_methods
             return _check_methods(C, "write")
         return NotImplemented