Lint: unused imports and correct annotation type

Author: rocky

xdis/codetype/code311.py

@@ -1,4 +1,4 @@
-# (C) Copyright 2020-2021, 2023 by Rocky Bernstein
+# (C) Copyright 2020-2021, 2023-2024 by Rocky Bernstein
 #
 #  This program is free software; you can redistribute it and/or
 #  modify it under the terms of the GNU General Public License
@@ -16,13 +16,12 @@
 
 import types
 from copy import deepcopy
+from dataclasses import dataclass
+from typing import Iterable, Iterator, Optional
 
 from xdis.codetype.code310 import Code310, Code310FieldTypes
 from xdis.version_info import PYTHON_VERSION_TRIPLE, version_tuple_to_str
 
-from dataclasses import dataclass
-from typing import Iterable, Iterator, Generator
-
 
 def parse_location_entries(location_bytes, first_line):
     """
@@ -227,7 +226,7 @@ def _test_check_bit(linetable_code_byte: int):
     return bool(linetable_code_byte & 128)
 
 
-def _go_to_next_code_byte(remaining_linetable: Iterator[int]) -> int:
+def _go_to_next_code_byte(remaining_linetable: Iterator[int]) -> Optional[int]:
     try:
         while not _test_check_bit((code_byte := next(remaining_linetable))):
             pass