}

  @Override
  Map<K, Collection<V>> createAsMap() {
    return new AsMap(map);
  }

  final Map<K, Collection<V>> createMaybeNavigableAsMap() {
    if (map instanceof NavigableMap) {
      return new NavigableAsMap((NavigableMap<K, Collection<V>>) map);
    } else if (map instanceof SortedMap) {