}
      return changed;
    }
  }

  /** SortedSet decorator that stays in sync with the multimap values for a key. */
  @WeakOuter
  class WrappedSortedSet extends WrappedCollection implements SortedSet<V> {
    WrappedSortedSet(
        @ParametricNullness K key, SortedSet<V> delegate, @Nullable WrappedCollection ancestor) {
      super(key, delegate, ancestor);
    }