final Comparator<? super T>[] comparators;

  @SuppressWarnings("unchecked") // Generic array creation
  CompoundOrdering(Comparator<? super T> primary, Comparator<? super T> secondary) {
    this.comparators = (Comparator<? super T>[]) new Comparator<?>[] {primary, secondary};
  }

  @SuppressWarnings("unchecked") // Generic array creation
  CompoundOrdering(Iterable<? extends Comparator<? super T>> comparators) {

   * the given {@code comparator}.
   *
   * @see #testComparator(Comparator, List)
   */
  public static <T extends @Nullable Object> void testComparator(
      Comparator<? super T> comparator, T... valuesInExpectedOrder) {
    testComparator(comparator, asList(valuesInExpectedOrder));
  }

  /**

    final E lastInclusive;
    private final Comparator<? super E> comparator;
    private final TestSortedSetGenerator<E> delegate;

    public SortedSetSubsetTestSetGenerator(
        TestSortedSetGenerator<E> delegate, Bound to, Bound from) {
      this.to = to;
      this.from = from;
      this.delegate = delegate;

      SortedSet<E> emptySet = delegate.create();
      this.comparator = emptySet.comparator();

    checkNotNull(values);
    if (values instanceof SortedSet) {
      SortedSet<C> set = (SortedSet<C>) values;
      Comparator<?> comparator = set.comparator();
      if (Ordering.<C>natural().equals(comparator) || comparator == null) {
        return closed(set.first(), set.last());
      }
    }
    Iterator<C> valueIterator = values.iterator();

    assertEquals("a", elementSet.last());
    assertEquals(comparator, elementSet.comparator());
  }

  public void testNullAcceptingComparator() throws Exception {
    Comparator<@Nullable String> comparator = Ordering.<String>natural().<String>nullsFirst();
    TreeMultiset<@Nullable String> ms = TreeMultiset.create(comparator);

    ms.add("b");
    ms.add(null);
    ms.add("a");
    ms.add("b");

    @SuppressWarnings({"unchecked", "nullness"})
    Comparator<@Nullable Object> unsafeComparator = (Comparator<@Nullable Object>) comparator;
    return unsafeComparator.compare(a, b);
  }

  final transient Comparator<? super E> comparator;

  ImmutableSortedSet(Comparator<? super E> comparator) {
    this.comparator = comparator;
  }

  /**

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());

  }

  @Override
  public void clear() {
    delegate.clear();
  }

  @Override
  public Comparator<? super K> comparator() {
    Comparator<? super K> comparator = delegate.comparator();
    if (comparator == null) {
      comparator = (Comparator<? super K>) NATURAL_ORDER;
    }
    return comparator;
  }

  @Override
  public boolean containsKey(Object key) {
    try {

  @SuppressWarnings({"unchecked", "nullness"})
  static int unsafeCompare(
      @CheckForNull Comparator<?> comparator, @CheckForNull Object o1, @CheckForNull Object o2) {
    if (comparator == null) {
      return ((Comparable<@Nullable Object>) o1).compareTo(o2);
    } else {
      return ((Comparator<@Nullable Object>) comparator).compare(o1, o2);
    }
  }

  /**