docs: def handle_message_registered(self, msg_data, host):
          """Processes messages that have been delivered by a registered client.
  
          Args:
            msg (string): The raw packet data delivered from the listener. This
              data will be unserialized and then processed based on the packet's
              method.
            host (tuple): The (address, host) tuple of the source message.
  
          Returns:
            A response that will be sent back to the client via the listener.
  
          """
          response = None
  
          if msg_data["method"] == "EVENT":
              logger.debug("<%s> <euuid:%s> Event message "
                           "received" % (msg_data["cuuid"], msg_data["euuid"]))
              response = self.event(msg_data["cuuid"],
                                    host,
                                    msg_data["euuid"],
                                    msg_data["event_data"],
                                    msg_data["timestamp"],
                                    msg_data["priority"])
  
          elif msg_data["method"] == "OK EVENT":
              logger.debug("<%s> <euuid:%s> Event confirmation message "
                           "received" % (msg_data["cuuid"], msg_data["euuid"]))
              try:
                  del self.event_uuids[msg_data["euuid"]]
              except KeyError:
                  logger.warning("<%s> <euuid:%s> Euuid does not exist in event "
                                 "buffer. Key was removed before we could process "
                                 "it." % (msg_data["cuuid"], msg_data["euuid"]))
  
          elif msg_data["method"] == "OK NOTIFY":
              logger.debug("<%s> <euuid:%s> Ok notify "
                           "received" % (msg_data["cuuid"], msg_data["euuid"]))
              try:
                  del self.event_uuids[msg_data["euuid"]]
              except KeyError:
                  logger.warning("<%s> <euuid:%s> Euuid does not exist in event "
                                 "buffer. Key was removed before we could process "
                                 "it." % (msg_data["cuuid"], msg_data["euuid"]))
  
  
          return response