def serialize(self):
        # Body
        # serialize_body should be implemented by subclass
        body = bytearray()
        body += self.serialize_body()

        # fixup
        self.length = len(body) + struct.calcsize(self._PACK_STR)

        # Header
        buf = bytearray()
        msg_pack_into(self._PACK_STR, buf, 0, self.type, self.length)
        buf += body

        # Pad
        pad_len = utils.round_up(self.length, 8) - self.length
        msg_pack_into(pad_len % "%dx", buf, len(buf))

        return buf
dataset/ETHPy150Open osrg/ryu/ryu/ofproto/ofproto_v1_4_parser.py/OFPPropBase.serialize/swapped operands of `%`