'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.'

def invalidate_permissions_cache(self):

    if self.user:
        self.user._authority_perm_cache_filled = False
    if self.group:
        self.group._authority_perm_cache_filled = False
