@Deprecated
    @Override
    public final ImmutableSortedMap<K, V> buildKeepingLast() {
      // TODO(emcmanus): implement
      throw new UnsupportedOperationException(
          "ImmutableSortedMap.Builder does not yet implement buildKeepingLast()");
    }
  }

  private final transient RegularImmutableSortedSet<K> keySet;
  private final transient ImmutableList<V> valueList;

 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Louis Wasserman
 * @since 12.0
 */
@GwtIncompatible // hasn't been tested yet
@ElementTypesAreNonnullByDefault
public abstract class ImmutableSortedMultiset<E> extends ImmutableMultiset<E>
    implements SortedMultiset<E> {
  // TODO(lowasser): GWT compatibility

  /**