def test_invalidCommand(self):
        """
        Test if an invalid command raises InvalidProxyError.
        """
        header = _makeHeaderIPv4(verCom=b'\x23')
        self.assertRaises(
            InvalidProxyHeader,
            _v2parser.V2Parser.parse,
            header,
        )

        Test if an invalid command raises InvalidProxyError.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/haproxy/test/test_v2parser.py