def test_whyDefault(self):
        """
        The C{"why"} value, when unspecified, defaults to C{"Unhandled Error"}.
        """
        try:
            raise RuntimeError()
        except:
            eventDict = dict(message=(), isError=1, failure=failure.Failure())
            text = log.textFromEventDict(eventDict)
            self.assertTrue(text.startswith("Unhandled Error\n"))

        The C{"why"} value, when unspecified, defaults to C{"Unhandled Error"}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_log.py