def kwargs(cls):
        """
        Keyword constructor arguments which are expected to result in an
        instance which returns C{bytes} when encoded.

        @return: A L{dict} of keyword arguments.
        """
        return dict(
            id=0,
            answer=False,
            opCode=dns.OP_QUERY,
            auth=False,
            trunc=False,
            recDes=False,
            recAv=False,
            rCode=0xabc, # Combined OPT extended RCODE + Message RCODE
            ednsVersion=0,
            dnssecOK=False,
            maxSize=4096,
            queries=[],
            answers=[],
            authority=[],
            additional=[],
        )

        Keyword constructor arguments which are expected to result in an
        instance which returns C{bytes} when encoded.

        @return: A L{dict} of keyword arguments.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_dns.py