CountingSupplier<TreeSet<Integer>> factory = new SortedSetSupplier();
    Map<Color, Collection<Integer>> map = Maps.newEnumMap(Color.class);
    SortedSetMultimap<Color, Integer> multimap = Multimaps.newSortedSetMultimap(map, factory);
    // newSortedSetMultimap calls the factory once to determine the comparator.
    assertEquals(1, factory.count);
    multimap.putAll(Color.BLUE, asList(3, 1, 4));
    assertEquals(2, factory.count);

      return new SortedSetMultimapBuilder<K0, V0>() {
        @Override
        public <K extends K0, V extends V0> SortedSetMultimap<K, V> build() {
          return Multimaps.newSortedSetMultimap(
              MultimapBuilderWithKeys.this.<K, V>createMap(), new TreeSetSupplier<V>(comparator));
        }
      };
    }

    /** Uses an {@link EnumSet} to store value collections. */

   * implement either {@link List} or {@code Set}! Use the more specific method {@link
   * #newListMultimap}, {@link #newSetMultimap} or {@link #newSortedSetMultimap} instead, to avoid
   * very surprising behavior from {@link Multimap#equals}.
   *
   * <p>The {@code factory}-generated and {@code map} classes determine the multimap iteration