Message 78018 - Python tracker

> > I'd rather see that integrated into collection: e.g. when iterating over
> > survivors of a collection, check whether they can be untracked.
> 
> That's what I had tried at first, but it crashes.

To be clearer, I tried adding it to the tp_traverse method of tuples. I
could try to add it to the collection machinery in gcmodule.c instead.