refix

Author: m-novikov

mypy/test/testmodulediscovery.py

@@ -17,7 +17,7 @@ def tear_down(self) -> None:
         self._teardown_mock_filesystem()
         find_module_clear_caches()
 
-    def _list_dir(self, path: str) -> List:
+    def _list_dir(self, path: str) -> List[str]:
         res = set()
 
         if not path.endswith(os.path.sep):