}
  }

  @GwtIncompatible // NavigableSet
  private static final class FilteredNavigableSet<E extends @Nullable Object>
      extends FilteredSortedSet<E> implements NavigableSet<E> {
    FilteredNavigableSet(NavigableSet<E> unfiltered, Predicate<? super E> predicate) {
      super(unfiltered, predicate);
    }

    NavigableSet<E> unfiltered() {
      return (NavigableSet<E>) unfiltered;
    }

  }

  @GwtIncompatible // NavigableSet
  static <E extends @Nullable Object> NavigableSet<E> navigableSet(
      NavigableSet<E> navigableSet, @Nullable Object mutex) {
    return new SynchronizedNavigableSet<>(navigableSet, mutex);
  }

  @GwtIncompatible // NavigableSet
  static <E extends @Nullable Object> NavigableSet<E> navigableSet(NavigableSet<E> navigableSet) {
    return navigableSet(navigableSet, null);

  }

  @GwtIncompatible // NavigableSet
  static <E extends @Nullable Object> NavigableSet<E> navigableSet(
      NavigableSet<E> navigableSet, @Nullable Object mutex) {
    return new SynchronizedNavigableSet<>(navigableSet, mutex);
  }

  @GwtIncompatible // NavigableSet
  static <E extends @Nullable Object> NavigableSet<E> navigableSet(NavigableSet<E> navigableSet) {
    return navigableSet(navigableSet, null);

  @WeakOuter
  final class WrappedNavigableSet extends WrappedSortedSet implements NavigableSet<V> {
    WrappedNavigableSet(
        @ParametricNullness K key, NavigableSet<V> delegate, @Nullable WrappedCollection ancestor) {
      super(key, delegate, ancestor);
    }

    @Override
    NavigableSet<V> getSortedSetDelegate() {
      return (NavigableSet<V>) super.getSortedSetDelegate();
    }

    @Override

   */
  @Override
  @GwtIncompatible // NavigableSet
  public NavigableSet<V> get(@ParametricNullness K key) {
    return (NavigableSet<V>) super.get(key);
  }

  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link
   * NavigableSet}, instead of the {@link java.util.Set} specified in the {@link Multimap}
   * interface.

  public Test testsForCheckedNavigableSet() {
    return SortedSetTestSuiteBuilder.using(
            new TestStringSortedSetGenerator() {
              @Override
              public NavigableSet<String> create(String[] elements) {
                NavigableSet<String> innerSet = new TreeSet<>();
                Collections.addAll(innerSet, elements);
                return Collections.checkedNavigableSet(innerSet, String.class);
              }

  }

  AbstractSortedMultiset(Comparator<? super E> comparator) {
    this.comparator = checkNotNull(comparator);
  }

  @Override
  public NavigableSet<E> elementSet() {
    return (NavigableSet<E>) super.elementSet();
  }

  @Override
  NavigableSet<E> createElementSet() {
    return new SortedMultisets.NavigableElementSet<>(this);
  }

  @Override
  public Comparator<? super E> comparator() {

  @Override
  public Comparator<? super E> comparator() {
    return delegate().comparator();
  }

  @Override
  NavigableSet<E> createElementSet() {
    return unmodifiableNavigableSet(delegate().elementSet());
  }

  @Override
  public NavigableSet<E> elementSet() {
    return (NavigableSet<E>) super.elementSet();
  }

  @LazyInit private transient @Nullable UnmodifiableSortedMultiset<E> descendingMultiset;

      result = Ordering.from(forwardMultiset().comparator()).reverse();
      comparator = result;
    }
    return result;
  }

  @LazyInit private transient @Nullable NavigableSet<E> elementSet;

  @Override
  public NavigableSet<E> elementSet() {
    NavigableSet<E> result = elementSet;
    if (result == null) {
      return elementSet = new SortedMultisets.NavigableElementSet<>(this);
    }
    return result;
  }

      List<String> list = Lists.newArrayList(elements);
      list.add("\0");
      list.add("zzz");
      return ImmutableSortedSet.copyOf(list).subSet("\0\0", "zzy");
    }
  }

  @GwtIncompatible // NavigableSet
  public static class ImmutableSortedSetDescendingGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {