<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def send(self, header, body):
 """ Send a message to GC :param header: message header :type header: :class:`steam.core.msg.GCMsgHdr` :param body: serialized body of the message :type body: :class:`bytes` """

        message = MsgProto(EMsg.ClientToGC)
        message.header.routing_appid = self.app_id
        message.body.appid = self.app_id
        message.body.msgtype = (set_proto_bit(header.msg)
                                if header.proto
                                else header.msg
                                )
        message.body.payload = header.serialize() + body
        self.steam.send(message)