Iterable<? extends @Nullable Object> iterable, @CheckForNull Object element) {
    if (iterable instanceof Collection) {
      Collection<?> collection = (Collection<?>) iterable;
      return Collections2.safeContains(collection, element);
    }
    return Iterators.contains(iterable.iterator(), element);
  }

  /**
   * Removes, from an iterable, every element that belongs to the provided collection.
   *

  @Override
  public int count(@CheckForNull Object element) {
    return delegate().count(element);
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    return delegate().add(element, occurrences);
  }

  @CanIgnoreReturnValue
  @Override
  public int remove(@CheckForNull Object element, int occurrences) {
    return delegate().remove(element, occurrences);

	default:
		return "unknown"
	}
}

// AccElem holds information for calculating an average value
type AccElem struct {
	Total int64
	Size  int64
	N     int64
}

// Add a duration to a single element.
func (a *AccElem) add(dur time.Duration) {
	if dur < 0 {
		dur = 0
	}
	a.Total += int64(dur)
	a.N++
}

// Merge b into a.
func (a *AccElem) merge(b AccElem) {
	a.N += b.N
	a.Total += b.Total

   * implementation for the creation of contents is independent and could be different from that of
   * the map under test.
   */
  Map<Element, Element> contents;

  /** Map pre-created before experiment starts to only measure iteration cost during experiment. */
  Map<Element, Element> map;

  CollectionBenchmarkSampleData elems;

  @Param({"0", "1", "100", "10000"})
  int elements;

  @BeforeExperiment

   */
  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public boolean add(E e) {
    return offer(e);
  }

  /**
   * Inserts the specified element into this priority queue.
   *
   * @param e the element to add
   * @return {@code true} (as specified by {@link Queue#offer})

      return standardAddAll(collection);
    }

    @Override
    public boolean add(T element) {
      return standardAdd(element);
    }

    @Override
    public void clear() {
      standardClear();
    }

    @Override
    public int count(Object element) {
      return standardCount(element);
    }

    @Override
    public boolean contains(Object object) {

    /**
     * 先頭に追加します。
     *
     * @param element
     *            追加するオブジェクト
     */
    public void addFirst(final E element) {
        header.next.addBefore(element);
    }

    /**
     * 最後に追加します。
     *
     * @param element
     *            追加するオブジェクト
     */
    public void addLast(final E element) {
        header.addBefore(element);
    }

    /**

  public E get(int index) {
    return delegate().get(index);
  }

  @Override
  public int indexOf(@CheckForNull Object element) {
    return delegate().indexOf(element);
  }

  @Override
  public int lastIndexOf(@CheckForNull Object element) {
    return delegate().lastIndexOf(element);
  }

  @Override
  public ListIterator<E> listIterator() {
    return delegate().listIterator();
  }

  @Override

  /**
   * Removes a single instance of the specified element from this queue, if it is present. More
   * formally, removes an element {@code e} such that {@code o.equals(e)}, if this queue contains
   * one or more such elements. Returns {@code true} if this queue contained the specified element
   * (or equivalently, if this queue changed as a result of the call).
   *
   * @param o element to be removed from this queue, if present

  @Override
  void setCountCheckReturnValue(E element, int count) {
    assertEquals(
        "multiset.setCount() should return the old count",
        getMultiset().count(element),
        setCount(element, count));
  }

  @Override
  void setCountNoCheckReturnValue(E element, int count) {
    setCount(element, count);
  }

  @CanIgnoreReturnValue
  private int setCount(E element, int count) {