K extends @Nullable Object, V extends @Nullable Object>
      extends UnmodifiableMultimap<K, V> implements ListMultimap<K, V> {
    UnmodifiableListMultimap(ListMultimap<K, V> delegate) {
      super(delegate);
    }

    @Override
    public ListMultimap<K, V> delegate() {
      return (ListMultimap<K, V>) super.delegate();
    }

    @Override
    public List<V> get(@ParametricNullness K key) {

      extends SynchronizedMultimap<K, V> implements ListMultimap<K, V> {
    SynchronizedListMultimap(ListMultimap<K, V> delegate, @CheckForNull Object mutex) {
      super(delegate, mutex);
    }

    @Override
    ListMultimap<K, V> delegate() {
      return (ListMultimap<K, V>) super.delegate();
    }

    @Override
    public List<V> get(K key) {