diff --git a/distutils/cmd.py b/distutils/cmd.py
index f2b5b964..22447850 100644
--- a/distutils/cmd.py
+++ b/distutils/cmd.py
@@ -12,7 +12,7 @@
 import sys
 from abc import abstractmethod
 from collections.abc import Callable, MutableSequence
-from typing import TYPE_CHECKING, Any, ClassVar, TypeVar, overload
+from typing import TYPE_CHECKING, Any, ClassVar, TypeVar, cast, overload
 
 from . import _modified, archive_util, dir_util, file_util, util
 from ._log import log
@@ -314,7 +314,8 @@ def get_finalized_command(self, command: str, create: bool = True) -> Command:
         'command', call its 'ensure_finalized()' method, and return the
         finalized command object.
         """
-        cmd_obj = self.distribution.get_command_obj(command, create)
+        # TODO: Raise a more descriptive error when create=False or cmd_obj is None ?
+        cmd_obj = cast(Command, self.distribution.get_command_obj(command, create))
         cmd_obj.ensure_finalized()
         return cmd_obj
 
diff --git a/distutils/command/build_py.py b/distutils/command/build_py.py
index d6ec7d10..59235837 100644
--- a/distutils/command/build_py.py
+++ b/distutils/command/build_py.py
@@ -360,6 +360,10 @@ def build_modules(self) -> None:
             self.build_module(module, module_file, package)
 
     def build_packages(self) -> None:
+        if self.packages is None:
+            raise TypeError(
+                f"{type(self).__name__}.packages is None. Is the Distribution missing packages ?"
+            )
         for package in self.packages:
             # Get list of (package, module, module_file) tuples based on
             # scanning the package directory.  'package' is only included
diff --git a/distutils/dist.py b/distutils/dist.py
index 3d45e5b0..42ee591f 100644
--- a/distutils/dist.py
+++ b/distutils/dist.py
@@ -1224,7 +1224,7 @@ def _read_list(name):
         self.description = _read_field('summary')
 
         if 'keywords' in msg:
-            self.keywords = _read_field('keywords').split(',')
+            self.keywords = _read_field('keywords').split(',')  # type:ignore[union-attr] # Manually checked
 
         self.platforms = _read_list('platform')
         self.classifiers = _read_list('classifier')
diff --git a/distutils/filelist.py b/distutils/filelist.py
index 8c76a5c6..97360b62 100644
--- a/distutils/filelist.py
+++ b/distutils/filelist.py
@@ -261,6 +261,7 @@ def include_pattern(
         # delayed loading of allfiles list
         if self.allfiles is None:
             self.findall()
+        assert self.allfiles is not None
 
         for name in self.allfiles:
             if pattern_re.search(name):
diff --git a/distutils/util.py b/distutils/util.py
index 19288d48..f97b686b 100644
--- a/distutils/util.py
+++ b/distutils/util.py
@@ -235,14 +235,9 @@ def grok_environment_error(exc: object, prefix: str = "error: ") -> str:
 
 
 # Needed by 'split_quoted()'
-_wordchars_re = _squote_re = _dquote_re = None
-
-
-def _init_regex():
-    global _wordchars_re, _squote_re, _dquote_re
-    _wordchars_re = re.compile(rf'[^\\\'\"{string.whitespace} ]*')
-    _squote_re = re.compile(r"'(?:[^'\\]|\\.)*'")
-    _dquote_re = re.compile(r'"(?:[^"\\]|\\.)*"')
+_wordchars_re = re.compile(rf'[^\\\'\"{string.whitespace} ]*')
+_squote_re = re.compile(r"'(?:[^'\\]|\\.)*'")
+_dquote_re = re.compile(r'"(?:[^"\\]|\\.)*"')
 
 
 def split_quoted(s: str) -> list[str]:
@@ -259,8 +254,6 @@ def split_quoted(s: str) -> list[str]:
     # This is a nice algorithm for splitting up a single string, since it
     # doesn't require character-by-character examination.  It was a little
     # bit of a brain-bender to get it working right, though...
-    if _wordchars_re is None:
-        _init_regex()
 
     s = s.strip()
     words = []
@@ -268,6 +261,7 @@ def split_quoted(s: str) -> list[str]:
 
     while s:
         m = _wordchars_re.match(s, pos)
+        assert m is not None
         end = m.end()
         if end == len(s):
             words.append(s[:end])
@@ -308,9 +302,6 @@ def split_quoted(s: str) -> list[str]:
     return words
 
 
-# split_quoted ()
-
-
 def execute(
     func: Callable[[Unpack[_Ts]], object],
     args: tuple[Unpack[_Ts]],
diff --git a/mypy.ini b/mypy.ini
index bbbe0fb7..80ac31ec 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -26,7 +26,6 @@ disable_error_code =
 	operator,
 	arg-type,
 	assignment,
-	union-attr,
 	misc,
 
 # stdlib's test module is not typed on typeshed