super(true, true, true);
  }

  private TreeMultimap<String, Integer> createMultimap() {
    TreeMultimap<String, Integer> multimap =
        TreeMultimap.create(
            Ordering.<String>natural().nullsFirst(), Ordering.<Integer>natural().nullsFirst());
    multimap.put("a", -1);
    multimap.put("a", -3);
    multimap.put("z", -2);
    return multimap;
  }

  @Override

    super(true, true, true);
  }

  private TreeMultimap<String, Integer> createMultimap() {
    TreeMultimap<String, Integer> multimap =
        TreeMultimap.create(
            Ordering.<String>natural().nullsFirst(), Ordering.<Integer>natural().nullsFirst());
    multimap.put("a", -1);
    multimap.put("a", -3);
    multimap.put("z", -2);
    return multimap;
  }

  @Override

            .named("SafeTreeSet with natural comparator")
            .createTestSuite());
    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {
                  @Override
                  protected Set<String> create(String[] elements) {
                    NavigableSet<String> set = new SafeTreeSet<>(Ordering.natural().nullsFirst());

            .named("SafeTreeSet with natural comparator")
            .createTestSuite());
    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {
                  @Override
                  protected Set<String> create(String[] elements) {
                    NavigableSet<String> set = new SafeTreeSet<>(Ordering.natural().nullsFirst());

    }
  }

  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();
  }

        builder.orderEntriesByValue(Ordering.natural()).build();
    assertMapEquals(keyOrdered, "four", 4, "one", 1);
    assertMapEquals(valueOrdered, "one", 1, "four", 4);
  }

  public void testBuilder_orderEntriesByValue_usedTwiceFails() {
    ImmutableBiMap.Builder<String, Integer> builder =
        new Builder<String, Integer>().orderEntriesByValue(Ordering.natural());
    try {

                  }

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

  }

  protected abstract Multiset<AnEnum> create(AnEnum[] elements);

  @Override
  public AnEnum[] createArray(int length) {
    return new AnEnum[length];
  }

  /** Sorts the enums according to their natural ordering. */
  @Override
  public List<AnEnum> order(List<AnEnum> insertionOrder) {
    Collections.sort(insertionOrder);
    return insertionOrder;
  }

        builder.orderEntriesByValue(Ordering.natural()).build();
    assertMapEquals(keyOrdered, "four", 4, "one", 1);
    assertMapEquals(valueOrdered, "one", 1, "four", 4);
  }

  public void testBuilder_orderEntriesByValue_usedTwiceFails() {
    ImmutableBiMap.Builder<String, Integer> builder =
        new Builder<String, Integer>().orderEntriesByValue(Ordering.natural());
    try {

 *
 * @author Louis Wasserman
 */
@GwtIncompatible
public final class SafeTreeSet<E> implements Serializable, NavigableSet<E> {
  @SuppressWarnings("unchecked")
  private static final Comparator<Object> NATURAL_ORDER =
      new Comparator<Object>() {
        @Override
        public int compare(Object o1, Object o2) {
          return ((Comparable<Object>) o1).compareTo(o2);
        }
      };