def test_startReceivingBoxes(self):
        """
        When L{amp.BinaryBoxProtocol} is connected to a transport, it calls
        C{startReceivingBoxes} on its L{IBoxReceiver} with itself as the
        L{IBoxSender} parameter.
        """
        protocol = amp.BinaryBoxProtocol(self)
        protocol.makeConnection(None)
        self.assertIs(self._boxSender, protocol)

        When L{amp.BinaryBoxProtocol} is connected to a transport, it calls
        C{startReceivingBoxes} on its L{IBoxReceiver} with itself as the
        L{IBoxSender} parameter.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_amp.py