- Based upon the value of the optional argument persist_at_shutdown,
- (NEVER, IF_NOT_LOADED, ALWAYS), the save() method of the class will
- be invoked just before program shutdown to give the class a chance
- to save its state somewhere.
+ Based upon the value of the optional argument
+ :code:`persist_at_shutdown` argument, (NEVER, IF_NOT_LOADED,
+ ALWAYS), the :meth:`save` method of the class will be invoked just
+ before program shutdown to give the class a chance to save its
+ state somewhere.
+
+ .. note::
+ The implementations of :meth:`save` and :meth:`load` and where the
+ class persists its state are details left to the :class:`Persistent`
+ implementation. Essentially this decorator just handles the
+ plumbing of calling your save/load and appropriate times and
+ creates a transparent global singleton whose state can be
+ persisted between runs.