def test_sillyEmptyThing(self):
        """
        Test that empty boxes raise an error; they aren't supposed to be sent
        on purpose.
        """
        a = amp.AMP()
        return self.assertRaises(amp.NoEmptyBoxes, a.ampBoxReceived, amp.Box())

        Test that empty boxes raise an error; they aren't supposed to be sent
        on purpose.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_amp.py