On Thu, May 20, 2021, 2:11 PM Chris Angelico 
Probably the easiest way would be to have some kind of unique identifier (a fully-qualified name) that can be pickled, and then any time you attempt to construct a Sentinel with that identifier, it's guaranteed to return the same object.

Gosh, almost like a UUID :-).

Actually, there's no reason my ._uuid attribute couldn't simply be the object id(). That's probably an improvement.