def test_none(self):
        """
        When L{SSHCiphers._getMAC} is called with the C{b"none"} MAC algorithm
        name it returns a tuple of (None, "", "", 0).
        """
        key = self.getSharedSecret()

        params = self.ciphers._getMAC(b"none", key)

        self.assertEqual((None, b"", b"", 0), params)

        When L{SSHCiphers._getMAC} is called with the C{b"none"} MAC algorithm
        name it returns a tuple of (None, "", "", 0).
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_transport.py