def test_descriptorObserver(self):
        """
        When used as a descriptor, the observer is propagated.
        """
        observed = []

        class MyObject(object):
            log = Logger(observer=observed.append)

        MyObject.log.info("hello")
        self.assertEqual(len(observed), 1)
        self.assertEqual(observed[0]['log_format'], "hello")

        When used as a descriptor, the observer is propagated.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_logger.py