@Override
  public ImmutableSortedSet<K> keySet() {
    ImmutableSortedSet<K> ks = keySet;
    return (ks == null) ? (keySet = createKeySet()) : ks;
  }

  @Override
  ImmutableSortedSet<K> createKeySet() {
    // the keySet() of the delegate is only a Set and TreeMap.navigatableKeySet
    // is not available in GWT yet.  To keep the code simple and code size more,

    @Override
    public SortedSet<K> keySet() {
      SortedSet<K> result = sortedKeySet;
      return (result == null) ? sortedKeySet = createKeySet() : result;
    }

    @Override
    SortedSet<K> createKeySet() {
      return new SortedKeySet(sortedMap());
    }
  }

  private final class NavigableAsMap extends SortedAsMap implements NavigableMap<K, Collection<V>> {

    ImmutableSet<K> result = keySet;
    return (result == null) ? keySet = createKeySet() : result;
  }

  /*
   * This could have a good default implementation of `return new ImmutableKeySet<K, V>(this)`, but
   * ProGuard can't figure out how to eliminate that default when RegularImmutableMap overrides it.
   */
  abstract ImmutableSet<K> createKeySet();

  UnmodifiableIterator<K> keyIterator() {

    ImmutableSet<K> result = keySet;
    return (result == null) ? keySet = createKeySet() : result;
  }

  /*
   * This could have a good default implementation of `return new ImmutableKeySet<K, V>(this)`, but
   * ProGuard can't figure out how to eliminate that default when RegularImmutableMap overrides it.
   */
  abstract ImmutableSet<K> createKeySet();

  UnmodifiableIterator<K> keyIterator() {

        return Spliterators.spliterator(this, Spliterator.ORDERED | Spliterator.DISTINCT);
      }
    }
    return new EntrySetImpl();
  }

  @Override
  Set<K> createKeySet() {
    @WeakOuter
    final class KeySetImpl extends KeySetView {
      @Override
      public @Nullable Object[] toArray() {
        return ObjectArrays.toArrayImpl(this);
      }

      @Override

    CustomMultimap(Map<K, Collection<V>> map, Supplier<? extends Collection<V>> factory) {
      super(map);
      this.factory = checkNotNull(factory);
    }

    @Override
    Set<K> createKeySet() {
      return createMaybeNavigableKeySet();
    }

    @Override
    Map<K, Collection<V>> createAsMap() {
      return createMaybeNavigableAsMap();
    }

    @Override

    CustomMultimap(Map<K, Collection<V>> map, Supplier<? extends Collection<V>> factory) {
      super(map);
      this.factory = checkNotNull(factory);
    }

    @Override
    Set<K> createKeySet() {
      return createMaybeNavigableKeySet();
    }

    @Override
    Map<K, Collection<V>> createAsMap() {
      return createMaybeNavigableAsMap();
    }

    @Override

    return false;
  }

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    return new ImmutableMapEntrySet.RegularEntrySet<>(this, entries);
  }

  @Override
  ImmutableSet<K> createKeySet() {
    return new KeySet<>(this);
  }

  private static final class KeySet<K> extends IndexedImmutableSet<K> {
    private final RegularImmutableMap<K, ?> map;

    KeySet(RegularImmutableMap<K, ?> map) {

      }
    }
  }

  @LazyInit private transient @Nullable Set<K> keySetView;

  @Override
  public Set<K> keySet() {
    return (keySetView == null) ? keySetView = createKeySet() : keySetView;
  }

  Set<K> createKeySet() {
    return new KeySetView();
  }

  @WeakOuter
  class KeySetView extends Maps.KeySet<K, V> {
    KeySetView() {
      super(CompactHashMap.this);
    }

      }
    }
  }

  @LazyInit private transient @Nullable Set<K> keySetView;

  @Override
  public Set<K> keySet() {
    return (keySetView == null) ? keySetView = createKeySet() : keySetView;
  }

  Set<K> createKeySet() {
    return new KeySetView();
  }

  @WeakOuter
  private final class KeySetView extends AbstractSet<K> {
    @Override
    public int size() {