iterator.remove();
    }
  }

  /** ValueIterator build on top of EntryIterator. */
  final class ValueIterator implements Iterator<V> {
    private EntryIterator iterator;

    ValueIterator() {
      iterator = new EntryIterator();
    }

    @Override
    public boolean hasNext() {
      return iterator.hasNext();
    }

    @Override
    public V next() {

    }

    @Override
    public boolean isEmpty() {
      synchronized (mutex) {
        return delegate().isEmpty();
      }
    }

    @Override
    public Iterator<E> iterator() {
      return delegate().iterator(); // manually synchronized
    }

    @Override
    public boolean remove(@CheckForNull Object o) {
      synchronized (mutex) {
        return delegate().remove(o);
      }

    }

    @Override
    public boolean isEmpty() {
      synchronized (mutex) {
        return delegate().isEmpty();
      }
    }

    @Override
    public Iterator<E> iterator() {
      return delegate().iterator(); // manually synchronized
    }

    @Override
    public Spliterator<E> spliterator() {
      synchronized (mutex) {
        return delegate().spliterator();
      }
    }

            Currency.PESO, Country.CHILE,
            Currency.FRANC, Country.SWITZERLAND);
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    Iterator<Currency> iter = bimap.keySet().iterator();
    assertEquals(Currency.DOLLAR, iter.next());
    iter.remove();

    // forward map ordered by currency
    assertThat(bimap.keySet()).containsExactly(Currency.FRANC, Currency.PESO).inOrder();

  /**
   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
   * this range map are guaranteed to read through to the returned {@code Map}.
   *
   * <p>The returned {@code Map} iterates over entries in ascending order of the bounds of the
   * {@code Range} entries.
   *
   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
   */
  Map<Range<K>, V> asMapOfRanges();

    return ImmutableSet.copyOf(elements);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> copyOf(Iterable<? extends E> elements) {
    return ImmutableSet.copyOf(elements);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> copyOf(Iterator<? extends E> elements) {
    return ImmutableSet.copyOf(elements);
  }

  public void testCreation_allDuplicates() {

   * <p>Iterators from the returned map are at least <i>weakly consistent</i>: they are safe for
   * concurrent use, but if the cache is modified (including by eviction) after the iterator is
   * created, it is undefined which of the changes (if any) will be reflected in that iterator.
   *
   * <p><b>Warning to users of Java 8+:</b> do not call any of the new <i>default methods</i> that

          // All collections are immutable empty. So safe for any type parameter.
          .put(Iterator.class, ImmutableSet.of().iterator())
          .put(PeekingIterator.class, Iterators.peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())
          .put(Collection.class, ImmutableList.of())

    assertThat(DoubleMath.mean(ImmutableList.of(11, -22, 44, -88).iterator()))
        .isWithin(1.0e-10)
        .of(-13.75);
    assertThat(DoubleMath.mean(ImmutableList.of(11).iterator())).isWithin(1.0e-10).of(11);
    assertThrows(
        IllegalArgumentException.class,
        () -> DoubleMath.mean(ImmutableList.<Integer>of().iterator()));
  }

  @GwtIncompatible // DoubleMath.mean

  private Entry<E> a;
  private Entry<E> b;
  private Entry<E> c;

  /** Used to avoid http://bugs.sun.com/view_bug.do?bug_id=6558557 */
  static <T> SortedMultiset<T> cast(Multiset<T> iterable) {
    return (SortedMultiset<T>) iterable;
  }

  @Override
  public void setUp() throws Exception {
    super.setUp();
    sortedMultiset = cast(getMultiset());
    entries =
        copyToList(