static volatile ILister l_persistentLister_instance;

static ILister l_persistentLister() {
  if (l_persistentLister_instance == null) {
    db();
    l_persistentLister_instance = uniq_sync(PersistentLister);
  }
  ret l_persistentLister_instance;
}

static void l_persistentLister(ILister l) {
  l_persistentLister_instance = l;
}