* *get* call in getValue but not for the *put* call here.)
                 *
                 * (Arguably we should use requireNonNull rather than uncheckedCastNullableTToT: We
                 * know that V is a non-null type because that's the only kind of value type that
                 * StandardTable supports. Thus, requireNonNull is safe as long as the cell is still

  public void testContainsAll() {
    Range<Integer> range = Range.closed(3, 5);
    assertTrue(range.containsAll(asList(3, 3, 4, 5)));
    assertFalse(range.containsAll(asList(3, 3, 4, 5, 6)));

    // We happen to know that natural-order sorted sets use a different code
    // path, so we test that separately
    assertTrue(range.containsAll(ImmutableSortedSet.of(3, 3, 4, 5)));
    assertTrue(range.containsAll(ImmutableSortedSet.of(3)));

        return unsafeNull(); // See the discussion in getValue().
      }
      /*
       * The cast is safe because updateIndex found the entry for this key. (If it hadn't, then we
       * would have returned above.) Thus, we know that it and its corresponding value are in
       * position `index`.
       */
      V oldValue = uncheckedCastNullableTToT(values[index]);
      if (Objects.equals(oldValue, value)) {
        return value;
      }

    assertThat(verifier.verify("\u2121.com", session)).isFalse()
    assertThat(verifier.verify("℡.com", session)).isFalse()

    // These should ideally be false, but we know that hostname is usually already checked by us
    assertThat(verifier.verify("\u212A.com", session)).isFalse()
    // Kelvin character below
    assertThat(verifier.verify("K.com", session)).isFalse()
  }

     * we can reference a node whose fields have been cleared is inside the iterator (and presumably
     * only under concurrent modification).
     *
     * To access these fields when you know that they are not null, call the pred() and succ()
     * methods, which perform null checks before returning the fields.
     */
    private @Nullable AvlNode<E> pred;
    private @Nullable AvlNode<E> succ;

    if (!iterator.hasNext()) {
      return Optional.absent();
    }

    /*
     * TODO(kevinb): consider whether this "optimization" is worthwhile. Users with SortedSets tend
     * to know they are SortedSets and probably would not call this method.
     */
    if (iterable instanceof SortedSet) {
      SortedSet<E> sortedSet = (SortedSet<E>) iterable;
      return Optional.of(sortedSet.last());
    }

   * - The map has not switched to delegating to a java.util implementation to mitigate hash
   *   flooding. Callers can confirm this by null-checking delegateOrNull().
   *
   * In an ideal world, we would document why we know those things are true every time we call these
   * methods. But that is a bit too painful....
   */

  private Object requireTable() {
    return requireNonNull(table);
  }

    if (!iterator.hasNext()) {
      return Optional.absent();
    }

    /*
     * TODO(kevinb): consider whether this "optimization" is worthwhile. Users with SortedSets tend
     * to know they are SortedSets and probably would not call this method.
     */
    if (iterable instanceof SortedSet) {
      SortedSet<E> sortedSet = (SortedSet<E>) iterable;
      return Optional.of(sortedSet.last());
    }

   */
  public static int frequency(Iterator<?> iterator, @Nullable Object element) {
    int count = 0;
    while (contains(iterator, element)) {
      // Since it lives in the same class, we know contains gets to the element and then stops,
      // though that isn't currently publicly documented.
      count++;
    }
    return count;
  }

  /**

   * both use cases by using @PolyNull. (By contrast, we can't use @PolyNull for our superinterface
   * (`implements Function<@PolyNull A, @PolyNull B>`), at least as far as I know.)
   */
  public Iterable<B> convertAll(Iterable<? extends A> fromIterable) {
    checkNotNull(fromIterable, "fromIterable");
    return () ->
        new Iterator<B>() {