gistfile1.py

class BadgeManager(Manager)  # This equals your BaseBadgeManager
    def get_by_id(self, roar_id, id_or_ids):
        pass

    def drop(self, roar_id, badge_id):
        pass


class BaseBadge(models.Model):
    
    objects = BadgeManager()

    class Meta:
        abstract = True


class PostBadgeManager(Manager):
    def get_by_roar_id(self, roar_id):
        pass

    def invalidate_key(self):
        self._model.CACHE_TEMPLATE  # This should be the way to use the cache attributes from the model
        pass

    @classmethod
    def get_cache_key(cls):
        cls._model.CACHE_TEMPLATE  # Not possible, model is None for classmethods
        pass


class PostBadge(BaseBadge):
    CACHE_TEMPLATE = ''
    posts_objects = PostBadgeManager()