}

  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1) {
    return ofInternal(Ordering.natural(), e1);
  }

  @SuppressWarnings("unchecked")
  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2) {
    return ofInternal(Ordering.natural(), e1, e2);
  }

  @SuppressWarnings("unchecked")

    assertEquals(tree, copyFromTree);
    assertThat(copyFromTree.keyComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.valueComparator()).isEqualTo(Ordering.natural());
    assertThat(copyFromTree.get(1.0).comparator()).isEqualTo(Ordering.natural());
  }

  /** Test that creating one TreeMultimap from a non-TreeMultimap results in natural ordering. */
  public void testCreateFromHashMultimap() {

        .addEqualityGroup(Ordering.natural())
        .testEquals();
    reserializeAndAssert(comparator);
    assertThat(comparator.toString())
        .isEqualTo("Ordering.natural().reverse().onResultOf(STRING_LENGTH)");
  }

  public void testLexicographical() {
    Ordering<String> ordering = Ordering.natural();
    Ordering<Iterable<String>> lexy = ordering.lexicographical();

        .addEqualityGroup(Ordering.natural())
        .testEquals();
    reserializeAndAssert(comparator);
    assertThat(comparator.toString())
        .isEqualTo("Ordering.natural().reverse().onResultOf(STRING_LENGTH)");
  }

  public void testLexicographical() {
    Ordering<String> ordering = Ordering.natural();
    Ordering<Iterable<String>> lexy = ordering.lexicographical();

  @SuppressWarnings("unchecked")
  static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private final transient SortedMap<K, V> sortedDelegate;

  // The comparator used by this map.  It's the same as that of sortedDelegate,
  // except that when sortedDelegate's comparator is null, it points to a
  // non-null instance of Ordering.natural().
  // (cpovirk: Is sortedDelegate's comparator really ever null?)

  }

  @Test
  public void nodeOrder_natural() {
    MutableGraph<Integer> graph =
        GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();

    addNodes(graph);

    assertThat(graph.nodeOrder()).isEqualTo(ElementOrder.sorted(Ordering.<Integer>natural()));
    assertThat(graph.nodes()).containsExactly(1, 3, 4).inOrder();
  }

  @Test
  public void nodeOrder_sorted() {

    ImmutableTable.Builder<Character, Integer, String> builder = ImmutableTable.builder();
    Table<Character, Integer, String> copy =
        builder
            .orderRowsBy(Ordering.natural())
            .orderColumnsBy(Ordering.natural())
            .putAll(table)
            .buildOrThrow();
    assertThat(copy.rowKeySet()).containsExactly('a', 'b').inOrder();
    assertThat(copy.columnKeySet()).containsExactly(1, 2).inOrder();

    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    assertTrue(
        SortedIterables.hasSameComparator(
            Ordering.natural().reverse(), Sets.newTreeSet(Ordering.natural().reverse())));
  }

  public void testComparator() {
    assertEquals(Ordering.natural(), SortedIterables.comparator(Sets.newTreeSet()));

   * of their natural ordering.
   */
  public static <E extends Comparable<?>> Builder<E> reverseOrder() {
    return new Builder<>(Collections.reverseOrder());
  }

  /**
   * Returns a builder that creates immutable sorted sets whose elements are ordered by their
   * natural ordering. The sorted sets use {@link Ordering#natural()} as the comparator. This method

   * ordering.
   *
   * @throws NullPointerException if any element is null
   */
  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E e1, E e2, E e3) {
    return copyOf(Ordering.natural(), Arrays.asList(e1, e2, e3));
  }

  /**
   * Returns an immutable sorted multiset containing the given elements sorted by their natural
   * ordering.
   *