return NavigableSetTestSuiteBuilder.using((TestSortedSetGenerator<K>) keySetGenerator);
  }

  public static final class NavigableMapSubmapTestMapGenerator<K, V>
      extends SortedMapSubmapTestMapGenerator<K, V> {
    public NavigableMapSubmapTestMapGenerator(
        TestSortedMapGenerator<K, V> delegate, Bound to, Bound from) {
      super(delegate, to, from);
    }

    @Override