def _rollback(self):
    try:
        query = self._make_rollback_query()
        try:
            self._connection_impl.privileged_execute(query)
        except BaseException:
            self._state = TransactionState.FAILED
            raise
        else:
            self._state = TransactionState.ROLLEDBACK
    finally:
        self._maybe_return()
def _rollback(self):
    try:
        query = self._make_rollback_query()
        try:
            self._connection_impl.privileged_execute(query)
        except BaseException:
            self._state = TransactionState.FAILED
            raise
        else:
            self._state = TransactionState.ROLLEDBACK
    finally:
        self._maybe_return()