def test_findNoFailureInExceptionHandler(self):
        """
        Within an exception handler, _findFailure should return
        L{None} in case no Failure is associated with the current
        exception.
        """
        try:
            1/0
        except:
            self.assertIsNone(failure.Failure._findFailure())
        else:
            self.fail("No exception raised from 1/0!?")

        Within an exception handler, _findFailure should return
        L{None} in case no Failure is associated with the current
        exception.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_failure.py