From my perspective type object is referenced by module state.
While module is present it's state hold all types exposed by module.
After module has deleted it's state has cleaned up and types has gone away — thats look good to me.

Instances of python classes (not extensions) hold ownership for it's class. I guess it done because python class can be constructed inside function and instance of this class should work after exit from that function like closure does.

In case of extension modules enough to hold type reference into module state itself.

Thoughts?