def tx_rollback(self):
self._send_method((<NUM_LIT>, <NUM_LIT:30>))<EOL>return self.wait(allowed_methods=[<EOL>(<NUM_LIT>, <NUM_LIT>),  <EOL>])<EOL>
Abandon the current transaction

        This method abandons all messages published and acknowledged
        in the current transaction.  A new transaction starts
        immediately after a rollback.