def test_jellyFailure(self):
        """
        Test that an exception which is a subclass of L{pb.Error} has more
        information passed across the network to the calling side.
        """
        def failureJelly(fail):
            fail.trap(JellyError)
            self.assertNotIsInstance(fail.type, str)
            self.assertIsInstance(fail.value, fail.type)
            return 43
        return self._testImpl('jelly', 43, failureJelly)

        Test that an exception which is a subclass of L{pb.Error} has more
        information passed across the network to the calling side.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/spread/test/test_pbfailure.py