def test_agentFailure(self):
        """
        verify that the client raises ConchError on AGENT_FAILURE
        """
        d = self.client.sendRequest(254, b'')
        self.pump.flush()
        return self.assertFailure(d, ConchError)

        verify that the client raises ConchError on AGENT_FAILURE
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_agent.py