}
      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);
    }

      } else if (collection instanceof NavigableSet) {
        return new WrappedNavigableSet(key, (NavigableSet<V>) collection, null);
      } else if (collection instanceof SortedSet) {
        return new WrappedSortedSet(key, (SortedSet<V>) collection, null);
      } else if (collection instanceof Set) {
        return new WrappedSet(key, (Set<V>) collection);
      } else {
        return new WrappedCollection(key, collection, null);