ClassToInstanceMap<Object> map = ImmutableClassToInstanceMap.copyOf(in);
    assertTrue(map.isEmpty());
  }

  public void testCopyOf_imap_valid() {
    ImmutableMap<Class<? extends Number>, ? extends Number> in =
        ImmutableMap.of(Number.class, 0, Double.class, Math.PI);
    ClassToInstanceMap<Number> map = ImmutableClassToInstanceMap.copyOf(in);
    assertEquals(2, map.size());

   */
  @CanIgnoreReturnValue
  public static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction) {
    return uniqueIndex(values, keyFunction, ImmutableMap.builder());
  }

  private static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction, ImmutableMap.Builder<K, V> builder) {
    checkNotNull(keyFunction);

   */
  @CanIgnoreReturnValue
  public static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction) {
    return uniqueIndex(values, keyFunction, ImmutableMap.builder());
  }

  private static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction, ImmutableMap.Builder<K, V> builder) {
    checkNotNull(keyFunction);

  /** Splits the key from the value. */
  private static final Splitter KEY_VALUE_SPLITTER = Splitter.on('=').trimResults();

  /** Map of names to ValueParser. */
  private static final ImmutableMap<String, ValueParser> VALUE_PARSERS =
      ImmutableMap.<String, ValueParser>builder()
          .put("initialCapacity", new InitialCapacityParser())
          .put("maximumSize", new MaximumSizeParser())

  /** Splits the key from the value. */
  private static final Splitter KEY_VALUE_SPLITTER = Splitter.on('=').trimResults();

  /** Map of names to ValueParser. */
  private static final ImmutableMap<String, ValueParser> VALUE_PARSERS =
      ImmutableMap.<String, ValueParser>builder()
          .put("initialCapacity", new InitialCapacityParser())
          .put("maximumSize", new MaximumSizeParser())

   * valueFunction))}.
   *
   * @throws NullPointerException if any element of this iterable is {@code null}, or if {@code
   *     valueFunction} produces {@code null} for any key
   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.

   * valueFunction))}.
   *
   * @throws NullPointerException if any element of this iterable is {@code null}, or if {@code
   *     valueFunction} produces {@code null} for any key
   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.

  }

  V getOrLoad(K key) throws ExecutionException {
    return get(key, defaultLoader);
  }

  ImmutableMap<K, V> getAllPresent(Iterable<?> keys) {
    int hits = 0;
    int misses = 0;

    ImmutableMap.Builder<K, V> result = ImmutableMap.builder();
    for (Object key : keys) {
      V value = get(key);
      if (value == null) {
        misses++;
      } else {

  }

  V getOrLoad(K key) throws ExecutionException {
    return get(key, defaultLoader);
  }

  ImmutableMap<K, V> getAllPresent(Iterable<?> keys) {
    int hits = 0;
    int misses = 0;

    ImmutableMap.Builder<K, V> result = ImmutableMap.builder();
    for (Object key : keys) {
      V value = get(key);
      if (value == null) {
        misses++;
      } else {