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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _send_rst(self, transaction):
 # pragma: no cover """ Sends an RST message for the response. :param transaction: transaction that holds the response """


        rst = Message()
        rst.type = defines.Types['RST']

        if not transaction.response.acknowledged:
            rst = self._messageLayer.send_empty(transaction, transaction.response, rst)
            self.send_datagram(rst)