diff --git a/cibuildwheel/windows.py b/cibuildwheel/windows.py
index 5c2d1f0a..37d2d7f4 100644
--- a/cibuildwheel/windows.py
+++ b/cibuildwheel/windows.py
@@ -175,7 +175,7 @@ def setup_setuptools_cross_compile(
         )
         return
     else:
-        atexit.register(lambda: distutils_cfg.unlink)
+        atexit.register(lambda: distutils_cfg.unlink())
 
     # Ensure our additional import libraries are made available, and explicitly
     # set the platform name
diff --git a/test/test_testing.py b/test/test_testing.py
index 8bff55aa..39e2d7cb 100644
--- a/test/test_testing.py
+++ b/test/test_testing.py
@@ -72,7 +72,7 @@ class TestSpam(TestCase):
 '''
 
 
-ADD_ENV = {}
+ADD_ENV: dict[str, str] = {}
 
 if utils.platform == "windows":
     if platform.machine() != "ARM64":