code: def rollback(self) -> None:
          
          if len(self._transactions) == 0:
              raise RuntimeError("rollback called outside transaction")
  
          _debug("rollback:", self._transactions[-1])
          # if something goes wrong here, nothing we can do about it, leave
          # database as is.
          try:
              # for every rollback action ...
              for on_rollback in self._transactions[-1]:
                  # execute it
                  _debug("--> rolling back", on_rollback)
                  self._do_with_retry(on_rollback)
          except:  # noqa: E722
              _debug("--> rollback failed")
              exc_class, exc, tb = sys.exc_info()
              raise tldap.exceptions.RollbackError(
                  "FATAL Unrecoverable rollback error: %r" % exc)
          finally:
              # reset everything to clean state
              _debug("--> rollback success")
              self.reset()
docs: Roll back to previous database state. However stay inside transaction
          management.