code: def _get_user_groups(session, user_id, filter):
          
          return session.fetch_items('groups.get', Group.from_json, count=1000, user_id=user_id, filter=filter, extended=1, fields=",".join(Group.GROUP_FIELDS))
docs: https://vk.com/dev/groups.get
  
          :param filter: {admin, editor, moder, groups, publics, events}
          :yield: Groups