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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 rollback(self):
 """Abandon the current transaction. Rollback all messages published during the current transaction session to the remote server. Note that all messages published during this transaction session will be lost, and will have to be published again. A new transaction session starts as soon as the command has been executed. :return: """

        self._tx_active = False
        return self._channel.rpc_request(specification.Tx.Rollback())