return new SetMultimapBuilder<K0, @Nullable Object>() {
        @Override
        public <K extends K0, V extends @Nullable Object> SetMultimap<K, V> build() {
          return Multimaps.newSetMultimap(
              MultimapBuilderWithKeys.this.createMap(),
              new HashSetSupplier<V>(expectedValuesPerKey));
        }
      };
    }

  }

  public void testNewSetMultimap() {
    CountingSupplier<Set<Integer>> factory = new SetSupplier();
    Map<Color, Collection<Integer>> map = new HashMap<>();
    SetMultimap<Color, Integer> multimap = Multimaps.newSetMultimap(map, factory);
    assertEquals(0, factory.count);
    multimap.putAll(Color.BLUE, asList(3, 1, 4));
    assertEquals(1, factory.count);
    multimap.putAll(Color.RED, asList(2, 7, 1, 8));

   *
   * <p><b>Warning: do not use</b> this method when the collections returned by {@code factory}
   * 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