QuerySet could be a collections.abc.Set.

[Alexandre Poitevin]

I don’t know if it’s intended, but QuerySet doesn’t inherit from collections.abc.Set although it implements its full API.
The only missing methods is __contains__ but the in is working anyway, fall-backing to the iteration protocol (through __iter__).

Pass it to the Set.register could also be considered.

I’m not sure if there is a clear win to this, or if it could include some non desired behaviors (like the possibility of unions with other Set types).

From a theoretical point of view it’s seems pretty logic – it’s called “QuerySet” by the way! –, however since practicality beats purity…

[Nick Pope]

I'm not sure that collections.abc.Set is the right abstract base class as it make no guarantee about order. A QuerySet is not equivalent to a set. Even collections.abc.Sequence is no good as that inherits from collections.abc.Reversible and QuerySet is not reversible. The best we could probably do is collections.abc.Collection...

[Mariusz Felisiak]

I don't see any benefits of inheriting from collections.abc in this case, and as Nick said, QuerySet is not a set. You can start a discussion on DevelopersMailingList if you don't agree.