def test_getTracebackObjectFromClean(self):
        """
        If the Failure has been cleaned, then C{getTracebackObject} returns an
        object that looks the same to L{traceback.extract_tb}.
        """
        f = getDivisionFailure()
        expected = traceback.extract_tb(f.getTracebackObject())
        f.cleanFailure()
        observed = traceback.extract_tb(f.getTracebackObject())
        self.assertIsNotNone(expected)
        self.assertEqual(expected, observed)

        If the Failure has been cleaned, then C{getTracebackObject} returns an
        object that looks the same to L{traceback.extract_tb}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_failure.py