@property<EOL><INDENT>def checkpoint_period(self):<DEDENT>
return self._checkpoint_period<EOL>
Enable checkpointing for the topology, and define the checkpoint
        period.

        When checkpointing is enabled, the state of all stateful operators
        is saved periodically.  If the operator restarts, its state is
        restored from the most recent checkpoint.

        The checkpoint period is the frequency at which checkpoints will
        be taken.  It can either be a :py:class:`~datetime.timedelta` value
        or a floating point value in seconds.  It must be at 0.001
        seconds or greater.

        A stateful operator is an operator whose callable is an instance of a
        Python callable class.

        Examples::

            # Create a topology that will checkpoint every thirty seconds
            topo = Topology()
            topo.checkpoint_period = 30.0

        ::

            # Create a topology that will checkpoint every two minutes
            topo = Topology()
            topo.checkpoint_period = datetime.timedelta(minutes=2)

        .. versionadded:: 1.11