make linters happier

testing/typing_checks.py

@@ -4,10 +4,10 @@
 none of the code triggers any mypy errors.
 """
 import contextlib
-from typing import assert_type
 from typing import Optional
 
 import pytest
+from typing_extensions import assert_type
 
 
 # Issue #7488.
@@ -28,8 +28,7 @@ def check_parametrize_ids_callable(func) -> None:
     pass
 
 
-def check_raises_is_a_context_manager() -> None:
-    a: bool
-    with pytest.raises(RuntimeError) if a else contextlib.nullcontext() as excinfo:
+def check_raises_is_a_context_manager(val: bool) -> None:
+    with pytest.raises(RuntimeError) if val else contextlib.nullcontext() as excinfo:
         pass
     assert_type(excinfo, Optional[pytest.ExceptionInfo[RuntimeError]])