def test_format(self):
        """
        The C{"format"} value, when specified, is used to format the message.
        """
        eventDict = dict(
            message=(), isError=0, format="Hello, %(foo)s!", foo="dude"
        )
        text = log.textFromEventDict(eventDict)
        self.assertEqual(text, "Hello, dude!")

        The C{"format"} value, when specified, is used to format the message.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_log.py