def invalidate_permissions_cache(self):
        """
        In the event that the Permission table is changed during the use of a
        permission the Permission cache will need to be invalidated and
        regenerated. By calling this method the invalidation will occur, and
        the next time the cached_permissions is used the cache will be
        re-primed.
        """
        if self.user:
            self.user._authority_perm_cache_filled = False
        if self.group:
            self.group._authority_perm_cache_filled = False
In the event that the Permission table is changed during the use of a
        permission the Permission cache will need to be invalidated and
        regenerated. By calling this method the invalidation will occur, and
        the next time the cached_permissions is used the cache will be
        re-primed.