*/
  public static <K extends @Nullable Object, V extends @Nullable Object>
      ListMultimap<K, V> unmodifiableListMultimap(ListMultimap<K, V> delegate) {
    if (delegate instanceof UnmodifiableListMultimap || delegate instanceof ImmutableListMultimap) {
      return delegate;
    }
    return new UnmodifiableListMultimap<>(delegate);
  }

  /**
   * Simply returns its argument.
   *

   */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      ListMultimap<K, V> unmodifiableListMultimap(ListMultimap<K, V> delegate) {
    if (delegate instanceof UnmodifiableListMultimap || delegate instanceof ImmutableListMultimap) {
      return delegate;
    }
    return new UnmodifiableListMultimap<>(delegate);
  }

  /**
   * Simply returns its argument.
   *

    ListMultimap<String, Integer> unmod = Multimaps.unmodifiableListMultimap(mod);
    assertThat(unmod).isNotSameInstanceAs(mod);
    assertThat(Multimaps.unmodifiableListMultimap(unmod)).isSameInstanceAs(unmod);
    ImmutableListMultimap<String, Integer> immutable =
        ImmutableListMultimap.of("a", 1, "b", 2, "a", 3);
    assertThat(Multimaps.unmodifiableListMultimap(immutable)).isSameInstanceAs(immutable);