static class StandardImplForwardingSet<T> extends ForwardingSet<T> {
    private final Set<T> backingSet;

    StandardImplForwardingSet(Set<T> backingSet) {
      this.backingSet = backingSet;
    }

    @Override
    protected Set<T> delegate() {
      return backingSet;
    }

    @Override
    public boolean equals(@Nullable Object object) {
      return standardEquals(object);
    }

  static class StandardImplForwardingSet<T> extends ForwardingSet<T> {
    private final Set<T> backingSet;

    StandardImplForwardingSet(Set<T> backingSet) {
      this.backingSet = backingSet;
    }

    @Override
    protected Set<T> delegate() {
      return backingSet;
    }

    @Override
    public boolean equals(@Nullable Object object) {
      return standardEquals(object);
    }

  static class StandardImplForwardingNavigableSet<T> extends ForwardingNavigableSet<T> {
    private final NavigableSet<T> backingSet;

    StandardImplForwardingNavigableSet(NavigableSet<T> backingSet) {
      this.backingSet = backingSet;
    }

    @Override
    protected NavigableSet<T> delegate() {
      return backingSet;
    }

    @Override
    public boolean equals(@Nullable Object object) {

    }

    @Override
    SortedSet<K> backingSet() {
      return (SortedSet<K>) super.backingSet();
    }

    @Override
    public @Nullable Comparator<? super K> comparator() {
      return backingSet().comparator();
    }

    @Override
    public Set<K> keySet() {
      return removeOnlySortedSet(backingSet());
    }

    @Override

    }

    @Override
    SortedSet<K> backingSet() {
      return (SortedSet<K>) super.backingSet();
    }

    @Override
    public @Nullable Comparator<? super K> comparator() {
      return backingSet().comparator();
    }

    @Override
    public Set<K> keySet() {
      return removeOnlySortedSet(backingSet());
    }

    @Override

                      public Set<Entry<String>> entrySet() {
                        Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

                          @Override