Use of django.db.models.signals.class_prepared in the wild?

[Jeremy Dunck]

Hello all,
I'm trying to document uses of django signals in preparation for a
presentation.
I'm having some trouble finding any uses of class_prepared.
I imagine this is because the class_prepared signal is sent so early
in Django's startup, but am curious:

Does anyone know of an example other than the deferred hookups in
Django itself?

-Jeremy