Set<Set<Integer>> expected = newHashSet();
    expected.add(ImmutableSet.<Integer>of());
    expected.add(ImmutableSet.of(1));
    expected.add(ImmutableSet.of(2));
    expected.add(ImmutableSet.of(3));
    expected.add(ImmutableSet.of(1, 2));
    expected.add(ImmutableSet.of(1, 3));
    expected.add(ImmutableSet.of(2, 3));
    expected.add(ImmutableSet.of(1, 2, 3));

      @SuppressWarnings({"nullness", "unchecked"}) // see supertype
      public ImmutableSet<@NonNull E> immutableCopy() {
        ImmutableSet.Builder<@NonNull E> builder =
            new ImmutableSet.Builder<@NonNull E>()
                .addAll((Iterable<@NonNull E>) set1)
                .addAll((Iterable<@NonNull E>) set2);
        return (ImmutableSet<@NonNull E>) builder.build();
      }
    };
  }

  /**

        builder.add(Types.getArrayClass(of(t.getGenericComponentType()).getRawType()));
      }
    }.visit(runtimeType);
    // Cast from ImmutableSet<Class<?>> to ImmutableSet<Class<? super T>>
    @SuppressWarnings({"unchecked", "rawtypes"})
    ImmutableSet<Class<? super T>> result = (ImmutableSet) builder.build();
    return result;
  }

  private boolean isOwnedBySubtypeOf(Type supertype) {

  }

  /** Returns an immutable set of the mappings in this map, sorted by the key ordering. */
  @Override
  public ImmutableSet<Entry<K, V>> entrySet() {
    return super.entrySet();
  }

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    class EntrySet extends ImmutableMapEntrySet<K, V> {
      @Override
      public UnmodifiableIterator<Entry<K, V>> iterator() {

  }

  private static void assertHasArrayInterfaces(TypeToken<?> arrayType) {
    assertEquals(arrayInterfaces(), ImmutableSet.copyOf(arrayType.getGenericInterfaces()));
  }

  private static ImmutableSet<TypeToken<?>> arrayInterfaces() {
    ImmutableSet.Builder<TypeToken<?>> builder = ImmutableSet.builder();
    for (Class<?> interfaceType : Object[].class.getInterfaces()) {
      builder.add(TypeToken.of(interfaceType));

  }

  private static void assertHasArrayInterfaces(TypeToken<?> arrayType) {
    assertEquals(arrayInterfaces(), ImmutableSet.copyOf(arrayType.getGenericInterfaces()));
  }

  private static ImmutableSet<TypeToken<?>> arrayInterfaces() {
    ImmutableSet.Builder<TypeToken<?>> builder = ImmutableSet.builder();
    for (Class<?> interfaceType : Object[].class.getInterfaces()) {
      builder.add(TypeToken.of(interfaceType));

    bimap.put("one", 1);
    BiMap<String, Integer> sync = Maps.synchronizedBiMap(bimap);
    bimap.put("two", 2);
    sync.put("three", 3);
    assertEquals(ImmutableSet.of(1, 2, 3), bimap.inverse().keySet());
    assertEquals(ImmutableSet.of(1, 2, 3), sync.inverse().keySet());
  }

  private static final Function<Integer, Double> SQRT_FUNCTION = in -> Math.sqrt(in);

  public void testTransformValues() {

    bimap.put("one", 1);
    BiMap<String, Integer> sync = Maps.synchronizedBiMap(bimap);
    bimap.put("two", 2);
    sync.put("three", 3);
    assertEquals(ImmutableSet.of(1, 2, 3), bimap.inverse().keySet());
    assertEquals(ImmutableSet.of(1, 2, 3), sync.inverse().keySet());
  }

  private static final Function<Integer, Double> SQRT_FUNCTION = in -> Math.sqrt(in);

  public void testTransformValues() {

  }

  /** Returns an immutable set of the mappings in this map, sorted by the key ordering. */
  @Override
  public ImmutableSet<Entry<K, V>> entrySet() {
    return super.entrySet();
  }

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    class EntrySet extends ImmutableMapEntrySet<K, V> {
      @Override
      public UnmodifiableIterator<Entry<K, V>> iterator() {

   *
   * <p>The {@link Iterable} equivalent of this method is {@link ImmutableSet#of()}.
   */
  static <T extends @Nullable Object> UnmodifiableIterator<T> emptyIterator() {
    return emptyListIterator();
  }

  /**
   * Returns the empty iterator.
   *
   * <p>The {@link Iterable} equivalent of this method is {@link ImmutableSet#of()}.
   */
  // Casting to any type is safe since there are no actual elements.