docs: def update_config(self):
          """ Updates or creates config of that group. Requires tree bound to db. """
          dataset = self._top._config.dataset
          session = object_session(self._top._config)
          logger.debug(
              'Updating group config. dataset: {}, type: {}, key: {}'.format(dataset.vid, self._top._type, self._key))
  
          self._config, created = _get_config_instance(
              self, session,
              parent_id=self._parent._config.id, d_vid=dataset.vid,
              group=self._key, key=self._key, type=self._top._type, dataset = dataset)
          if created:
              self._top._cached_configs[self._get_path()] = self._config
          self._top._add_valid(self._config)
  
          if created:
              logger.debug(
                  'New group config created and linked. config: {}'.format(self._config))
          else:
              logger.debug(
                  'Existing group config linked. config: {}'.format(self._config))