.allowsSelfLoops(true)
            .nodeOrder(ElementOrder.<String>natural())
            .immutable()
            .build();

    assertThat(emptyGraph.isDirected()).isTrue();
    assertThat(emptyGraph.allowsSelfLoops()).isTrue();
    assertThat(emptyGraph.nodeOrder()).isEqualTo(ElementOrder.<String>natural());
  }

  /**

   * 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.
   *

                Collections.addAll(innerSet, elements);
                return Collections.checkedNavigableSet(innerSet, String.class);
              }
            })
        .named("checkedNavigableSet/TreeSet, natural")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.KNOWN_ORDER,
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION,

                    return TreeMultiset.create(asList(elements));
                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return Ordering.natural().sortedCopy(insertionOrder);
                  }
                })
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,

  /**
   * Creates an empty {@code TreeMultimap} ordered by the natural ordering of its keys and values.
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() {
    return new TreeMultimap<>(Ordering.natural(), Ordering.natural());
  }

  /**

    }
  }

  public void testBuilderGenerics_selfComparable() {
    // testing simple creation
    ImmutableSortedSet.Builder<SelfComparableExample> natural = ImmutableSortedSet.naturalOrder();
    assertThat(natural).isNotNull();
    ImmutableSortedSet.Builder<SelfComparableExample> reverse = ImmutableSortedSet.reverseOrder();
    assertThat(reverse).isNotNull();
  }

    }
  }

  public enum ComparatorType {
    CHEAP {
      @Override
      public Comparator<Integer> get() {
        return Ordering.natural();
      }
    },
    EXPENSIVE {
      @Override
      public Comparator<Integer> get() {
        return Ordering.natural().onResultOf(new ExpensiveComputation());
      }
    };

    public abstract Comparator<Integer> get();
  }

 *       directly
 *   <li>Pass a <i>pre-existing</i> {@link Comparator} instance to {@link #from(Comparator)}
 *   <li>Use the natural ordering, {@link Ordering#natural}
 * </ul>
 *
 * <h4>Chaining</h4>
 *
 * <p>Then you can use the <i>chaining</i> methods to get an altered version of that {@code
 * Ordering}, including:
 *
 * <ul>
 *   <li>{@link #reverse}

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.Iterator;

/** An ordering that uses the reverse of the natural order of the values. */
@GwtCompatible
final class ReverseNaturalOrdering extends Ordering<Comparable<?>> implements Serializable {
  static final ReverseNaturalOrdering INSTANCE = new ReverseNaturalOrdering();

  @Override

    assertThat(copy.keySet()).containsExactly("google", "tree").inOrder();
    assertThat(copy.get("google")).containsExactly(2, 6).inOrder();
    assertEquals(Ordering.natural(), copy.keyComparator());
    assertEquals(Ordering.natural(), copy.valueComparator());
    assertEquals(Ordering.natural(), copy.get("google").comparator());
  }

  public void testToString() {
    Multimap<String, Integer> multimap = create();
    multimap.put("foo", 3);