def test_excInfo(self):
        """
        L{excInfoOrFailureToExcInfo} returns exactly what it is passed, if it is
        passed a tuple like the one returned by L{sys.exc_info}.
        """
        info = (ValueError, ValueError("foo"), None)
        self.assertTrue(info is excInfoOrFailureToExcInfo(info))

        L{excInfoOrFailureToExcInfo} returns exactly what it is passed, if it is
        passed a tuple like the one returned by L{sys.exc_info}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_util.py