def METHOD_NAME(obj):
    ct_id = getattr(obj, ct_attname)
    if ct_id is None:
        return None
    else:
        if model := self.get_content_type(
            id=ct_id, using=obj._state.db
        ).model_class():
            return (
                model._meta.pk.get_prep_value(getattr(obj, self.fk_field)),
                model,
            )
        return None