def test_message(self):
        """
        The C{"message"} value, when specified, is concatenated to generate the
        message.
        """
        eventDict = dict(message=("a", "b", "c"))
        text = log.textFromEventDict(eventDict)
        self.assertEqual(text, "a b c")

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