code: def ack(self, id, transaction=None, receipt=None):
          
          assert id is not None, "'id' is required"
          headers = {HDR_MESSAGE_ID: id}
          if transaction:
              headers[HDR_TRANSACTION] = transaction
          if receipt:
              headers[HDR_RECEIPT] = receipt
          self.send_frame(CMD_ACK, headers)
docs: Acknowledge 'consumption' of a message by id.
  
          :param str id: identifier of the message
          :param str transaction: include the acknowledgement in the specified transaction