derivedSuites.add(createDescendingSuite(parentBuilder));
    }
    return derivedSuites;
  }

  public static final class NavigableSetSubsetTestSetGenerator<E>
      extends SortedSetSubsetTestSetGenerator<E> {
    public NavigableSetSubsetTestSetGenerator(
        TestSortedSetGenerator<E> delegate, Bound to, Bound from) {
      super(delegate, to, from);
    }

    @Override