docs: def local_manager_is_default(self, adm_gid, gid):
          """Check whether gid is default group for local manager group.
          """
          config = self.root['settings']['ugm_localmanager'].attrs
          rule = config[adm_gid]
          if gid not in rule['target']:
              raise Exception(u"group '%s' not managed by '%s'" % (gid, adm_gid))
          return gid in rule['default']