def test_saveLoadUnknownLevel(self):
        """
        If a saved bit of JSON (let's say, from a future version of Twisted)
        were to persist a different log_level, it will resolve as None.
        """
        loadedEvent = eventFromJSON(
            '{"log_level": {"name": "other", '
            '"__class_uuid__": "02E59486-F24D-46AD-8224-3ACDF2A5732A"}}'
        )
        self.assertEqual(loadedEvent, dict(log_level=None))

        If a saved bit of JSON (let's say, from a future version of Twisted)
        were to persist a different log_level, it will resolve as None.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_json.py