code: def _prime_group_perm_caches(self):
          
          perm_cache = self._get_group_cached_perms()
          self.group._authority_perm_cache = perm_cache
          self.group._authority_perm_cache_filled = True
docs: Prime the group cache and put them on the ``self.group``.
          In addition add a cache filled flag on ``self.group``.