def test_receivedAsk(self):
        """
        L{CommandDispatcher.ampBoxReceived} should locate the appropriate
        command in its responder lookup, based on the '_ask' key.
        """
        received = []
        def thunk(box):
            received.append(box)
            return amp.Box({"hello": "goodbye"})
        input = amp.Box(_command="hello",
                        _ask="test-command-id",
                        hello="world")
        self.locator.commands['hello'] = thunk
        self.dispatcher.ampBoxReceived(input)
        self.assertEqual(received, [input])

        L{CommandDispatcher.ampBoxReceived} should locate the appropriate
        command in its responder lookup, based on the '_ask' key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_amp.py