Comparator<String[]> comparator =
        Ordering.natural().lexicographical().onResultOf(Arrays::asList);
    String[] array = new String[] {"a"};
    Multiset<String[]> multiset = ImmutableSortedMultiset.orderedBy(comparator).add(array).build();
    Multiset<String[]> expected = HashMultiset.create();
    expected.add(array);
    assertEquals(expected, multiset);
  }

  public void testCreation_arrayContainingOnlyNull() {

   * SortedSet<Integer>} with a {@code Comparator<Number>}, use the {@link Builder} constructor
   * instead.
   *
   * @throws NullPointerException if {@code comparator} is null
   */
  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<>(comparator);
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.

   * SortedSet<Integer>} with a {@code Comparator<Number>}, use the {@link Builder} constructor
   * instead.
   *
   * @throws NullPointerException if {@code comparator} is null
   */
  public static <E> Builder<E> orderedBy(Comparator<E> comparator) {
    return new Builder<>(comparator);
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by the reverse
   * of their natural ordering.

    }
    map.put(key, value);
  }

  public static <K extends Comparable<?>, V> Builder<K, V> naturalOrder() {
    return new Builder<K, V>(Ordering.natural());
  }

  public static <K, V> Builder<K, V> orderedBy(Comparator<K> comparator) {
    return new Builder<K, V>(comparator);
  }

  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<K, V>(Ordering.natural().reverse());
  }