* [1..∞)}.
   *
   * @throws NoSuchElementException if this set is empty
   */
  public abstract Range<C> range(BoundType lowerBoundType, BoundType upperBoundType);

  @Override
  @GwtIncompatible // NavigableSet
  ImmutableSortedSet<C> createDescendingSet() {
    return new DescendingImmutableSortedSet<>(this);
  }

   * [1..∞)}.
   *
   * @throws NoSuchElementException if this set is empty
   */
  public abstract Range<C> range(BoundType lowerBoundType, BoundType upperBoundType);

  @Override
  @GwtIncompatible // NavigableSet
  ImmutableSortedSet<C> createDescendingSet() {
    return new DescendingImmutableSortedSet<>(this);
  }