}

  /**
   * Creates an empty {@code TreeMultimap} instance using explicit comparators. Neither comparator
   * may be null; use {@link Ordering#natural()} to specify natural order.
   *
   * @param keyComparator the comparator that determines the key ordering
   * @param valueComparator the comparator that determines the value ordering
   */

   *
   * @param comparator the comparator that defines the order
   * @return comparator itself if it is already an {@code Ordering}; otherwise an ordering that
   *     wraps that comparator
   */
  public static <T extends @Nullable Object> Ordering<T> from(Comparator<T> comparator) {
    return (comparator instanceof Ordering)
        ? (Ordering<T>) comparator
        : new ComparatorOrdering<T>(comparator);

  private static final Comparator<@Nullable Integer> DECREASING_INT_COMPARATOR =
      Ordering.<Integer>natural().reverse().<Integer>nullsFirst();

  private SetMultimap<String, Integer> create() {
    return TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
  }

  /** Create and populate a {@code TreeMultimap} with explicit comparators. */

   *
   * @since 11.0
   */
  @DoNotMock
  public static final class Builder<R, C, V> {
    private final List<Cell<R, C, V>> cells = new ArrayList<>();
    private @Nullable Comparator<? super R> rowComparator;
    private @Nullable Comparator<? super C> columnComparator;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableTable#builder}.
     */

   *
   * @since 11.0
   */
  @DoNotMock
  public static final class Builder<R, C, V> {
    private final List<Cell<R, C, V>> cells = new ArrayList<>();
    private @Nullable Comparator<? super R> rowComparator;
    private @Nullable Comparator<? super C> columnComparator;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableTable#builder}.
     */

      return toString;
    }
  }

  /**
   * Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;
  }

  /**

      return toString;
    }
  }

  /**
   * Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;
  }

  /**

    Comparator<Comparable<?>> comparator = Ordering.natural().reverse();
    SortedSet<String> set =
        new ImmutableSortedSet.Builder<String>(comparator).add("a", "b", "c").build();
    SortedSet<String> copy = SerializableTester.reserializeAndAssert(set);
    assertTrue(elementsEqual(set, copy));
    assertEquals(set.comparator(), copy.comparator());
  }

  public void testReverseOrder() {

    Comparator<Comparable<?>> comparator = Ordering.natural().reverse();
    SortedSet<String> set =
        new ImmutableSortedSet.Builder<String>(comparator).add("a", "b", "c").build();
    SortedSet<String> copy = SerializableTester.reserializeAndAssert(set);
    assertTrue(elementsEqual(set, copy));
    assertEquals(set.comparator(), copy.comparator());
  }

  public void testReverseOrder() {

    // The VarHandle, Unsafe, or Java implementation.
    Comparator<byte[]> comparator = UnsignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
    assertThat(SerializableTester.reserialize(comparator)).isSameInstanceAs(comparator);

    // The Java implementation.
    Comparator<byte[]> javaImpl = UnsignedBytes.lexicographicalComparatorJavaImpl();