def test_asynchronousException(self):
        """
        Test that a Deferred returned by a remote method which already has a
        Failure correctly has that error passed back to the calling side.
        """
        return self._exceptionTest(
            'asynchronousException', AsynchronousException, True)

        Test that a Deferred returned by a remote method which already has a
        Failure correctly has that error passed back to the calling side.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/spread/test/test_pbfailure.py