ImmutableSetMultimap.<String, String>builder().orderValuesBy(Ordering.natural());
    assertThrows(IllegalArgumentException.class, () -> builder.expectedValuesPerKey(-1));
  }

  public void testBuilderWithExpectedValuesPerKeyZeroOrderValuesBy() {
    ImmutableSetMultimap.Builder<String, String> builder =
        ImmutableSetMultimap.<String, String>builder()
            .orderValuesBy(Ordering.natural())

     *
     * @since 8.0
     */
    // TODO: Make serialization behavior consistent.
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> orderValuesBy(Comparator<? super V> valueComparator) {
      super.orderValuesBy(valueComparator);
      return this;
    }

    /** Returns a newly-created immutable set multimap. */
    @Override
    public ImmutableSetMultimap<K, V> build() {

     *
     * @since 8.0
     */
    // TODO: Make serialization behavior consistent.
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> orderValuesBy(Comparator<? super V> valueComparator) {
      super.orderValuesBy(valueComparator);
      return this;
    }

    /** Returns a newly-created immutable set multimap. */
    @Override
    public ImmutableSetMultimap<K, V> build() {

      return this;
    }

    /**
     * Specifies the ordering of the generated multimap's values for each key.
     *
     * @since 8.0
     */
    @CanIgnoreReturnValue
    public Builder<K, V> orderValuesBy(Comparator<? super V> valueComparator) {
      this.valueComparator = checkNotNull(valueComparator);
      return this;
    }

    @CanIgnoreReturnValue
    Builder<K, V> combine(Builder<K, V> other) {

    ImmutableListMultimap.Builder<String, Integer> builder = ImmutableListMultimap.builder();
    builder.put("b", 3);
    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderValuesBy(Collections.reverseOrder());
    builder.put("c", 4);
    builder.put("a", 2);
    builder.put("b", 6);
    ImmutableListMultimap<String, Integer> multimap = builder.build();

    ImmutableListMultimap.Builder<String, Integer> builder = ImmutableListMultimap.builder();
    builder.put("b", 3);
    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderValuesBy(Collections.reverseOrder());
    builder.put("c", 4);
    builder.put("a", 2);
    builder.put("b", 6);
    ImmutableListMultimap<String, Integer> multimap = builder.build();

     */
    @SuppressWarnings("unchecked")
    ImmutableList<E> buildSorted(Comparator<? super E> comparator) {
      // Currently only used by ImmutableListMultimap.Builder.orderValuesBy.
      // In particular, this implies that the comparator can never get "removed," so this can't
      // invalidate future builds.

      copyOnWrite = true;
      Arrays.sort((E[]) contents, 0, size, comparator);