def test_macs(self):
        """
        Like test_ciphers, but for the various MACs.
        """
        deferreds = []
        for mac in transport.SSHTransportBase.supportedMACs + [b'none']:
            def setMAC(proto):
                proto.supportedMACs = [mac]
                return proto
            deferreds.append(self._runClientServer(setMAC))
        return defer.DeferredList(deferreds, fireOnOneErrback=True)

        Like test_ciphers, but for the various MACs.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_transport.py