fix mypy failure after multiple merges

Author: Avasam

setuptools/command/install.py

@@ -4,7 +4,7 @@
 import inspect
 import platform
 from collections.abc import Callable
-from typing import Any, ClassVar, cast
+from typing import TYPE_CHECKING, Any, ClassVar, cast
 
 import setuptools
 
@@ -15,6 +15,12 @@
 import distutils.command.install as orig
 from distutils.errors import DistutilsArgError
 
+if TYPE_CHECKING:
+    # This is only used for a type-cast, don't import at runtime or it'll cause deprecation warnings
+    from .easy_install import easy_install as easy_install_cls
+else:
+    easy_install_cls = None
+
 # Prior to numpy 1.9, NumPy relies on the '_install' name, so provide it for
 # now. See https://github.com/pypa/setuptools/issues/199/
 _install = orig.install
@@ -131,7 +137,9 @@ def _called_from_setup(run_frame):
         return False
 
     def do_egg_install(self) -> None:
-        easy_install = self.distribution.get_command_class('easy_install')
+        easy_install = cast(
+            type[easy_install_cls], self.distribution.get_command_class('easy_install')
+        )
 
         cmd = easy_install(
             self.distribution,