def _register_parser(cls):
    assert cls.cls_msg_type is not None
    assert cls.cls_msg_type not in _MSG_PARSERS
    _MSG_PARSERS[cls.cls_msg_type] = cls.parser
    return cls
class decorator to register msg parser
dataset/ETHPy150Open osrg/ryu/ryu/ofproto/ofproto_v1_5_parser.py/_register_parser