Replace | None with Optional.

Author: nedtwigg

python/selfie-lib/selfie_lib/LineReader.py

@@ -1,4 +1,5 @@
 import io
+from typing import Optional
 
 
 def _to_unix(s: str) -> str:
@@ -30,7 +31,7 @@ def __detect_newline_type(self) -> bool:
     def unix_newlines(self) -> bool:
         return self.__uses_unix_newlines
 
-    def read_line(self) -> str | None:
+    def read_line(self) -> Optional[str]:
         line_bytes = self.__buffer.readline()
         if line_bytes == b"":
             return None

python/selfie-lib/selfie_lib/Literals.py

@@ -2,7 +2,7 @@
 import re
 from abc import abstractmethod
 from enum import Enum, auto
-from typing import Any, Protocol, TypeVar
+from typing import Any, Optional, Protocol, TypeVar
 
 from .EscapeLeadingWhitespace import EscapeLeadingWhitespace
 
@@ -22,7 +22,7 @@ def from_filename(cls, filename: str) -> "Language":
 
 
 class LiteralValue:
-    def __init__(self, expected: T | None, actual: T, fmt: "LiteralFormat") -> None:
+    def __init__(self, expected: Optional[T], actual: T, fmt: "LiteralFormat") -> None:
         self.expected = expected
         self.actual = actual
         self.format = fmt

python/selfie-lib/selfie_lib/SnapshotValueReader.py

@@ -17,10 +17,10 @@ class SnapshotValueReader:
 
     def __init__(self, line_reader: LineReader):
         self.line_reader = line_reader
-        self.line: str | None = None
+        self.line: Optional[str] = None
         self.unix_newlines = self.line_reader.unix_newlines()
 
-    def peek_key(self) -> str | None:
+    def peek_key(self) -> Optional[str]:
         return self.__next_key()
 
     def next_value(self) -> SnapshotValue: