Type Command.sub_commands to avoid variance issues

distutils/cmd.py

@@ -4,10 +4,14 @@
 in the distutils.command package.
 """
 
+from __future__ import annotations
+
 import logging
 import os
 import re
 import sys
+from collections.abc import Callable
+from typing import Any, ClassVar
 
 from . import _modified, archive_util, dir_util, file_util, util
 from ._log import log
@@ -44,7 +48,9 @@ class Command:
     # 'sub_commands' is usually defined at the *end* of a class, because
     # predicates can be unbound methods, so they must already have been
     # defined.  The canonical example is the "install" command.
-    sub_commands = []
+    sub_commands: ClassVar[  # Any to work around variance issues
+        list[tuple[str, Callable[[Any], bool] | None]]
+    ] = []
 
     # -- Creation/initialization methods -------------------------------