code: def pack(self, update_timestamp=False, insert_before_payload=""):
          
          return self._header.pack(update_timestamp) \
              + insert_before_payload \
              + self._payload
docs: Pack this object into a transmittable format
  
          :param update_timestamp:
              Should the timestamp be updated to current (default: False)
          :type update_timestamp: bool
          :param insert_before_payload: Insert this after this data, but before
              payload (default: "")
          :type insert_before_payload: str
          :return: Packed data
          :rtype: str
          :raises ValueError: Invalid deviceId