}

    @Override
    public boolean addAll(int index, Collection<? extends T> elements) {
      return standardAddAll(index, elements);
    }

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

    @Override
    public boolean contains(Object object) {
      return standardContains(object);
    }

    @Override
    public boolean containsAll(Collection<?> collection) {

    }

    @Override
    public boolean addAll(Collection<? extends E> collection) {
      return standardAddAll(collection);
    }

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

    @Override
    public boolean contains(@Nullable Object object) {
      return standardContains(object);
    }

    @Override
    public boolean containsAll(Collection<?> collection) {

    }

    @Override
    public boolean addAll(Collection<? extends T> collection) {
      return standardAddAll(collection);
    }

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

    @Override
    public boolean contains(Object object) {
      return standardContains(object);
    }

    @Override
    public boolean containsAll(Collection<?> collection) {

        @Override
        public Iterator<Entry<K, V>> iterator() {
          return backingSortedMap.entrySet().iterator();
        }
      };
    }

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

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public SortedMap<K, V> subMap(K fromKey, K toKey) {

   * #entrySet}. If you override {@link #entrySet}, you may wish to override {@link #clear} to
   * forward to this implementation.
   *
   * @since 7.0
   */
  @Override
  protected void standardClear() {
    Iterators.clear(entrySet().iterator());
  }

  /**
   * A sensible, albeit inefficient, definition of {@link #count} in terms of {@link #entrySet}. If

   * #entrySet}. In many cases, you may wish to override {@link #clear} to forward to this
   * implementation.
   *
   * @since 7.0
   */
  protected void standardClear() {
    Iterators.clear(entrySet().iterator());
  }

  /**
   * A sensible implementation of {@link Map#keySet} in terms of the following methods: {@link

      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) {

   * #entrySet}. In many cases, you may wish to override {@link #clear} to forward to this
   * implementation.
   *
   * @since 7.0
   */
  protected void standardClear() {
    Iterators.clear(entrySet().iterator());
  }

  /**
   * A sensible implementation of {@link Map#keySet} in terms of the following methods: {@link

   * {@code remove} method. If you override {@link #iterator}, you may wish to override {@link
   * #clear} to forward to this implementation.
   *
   * @since 7.0
   */
  protected void standardClear() {
    Iterators.clear(iterator());
  }

  /**
   * A sensible definition of {@link #isEmpty} as {@code !iterator().hasNext}. If you override

   * {@code remove} method. If you override {@link #iterator}, you may wish to override {@link
   * #clear} to forward to this implementation.
   *
   * @since 7.0
   */
  protected void standardClear() {
    Iterators.clear(iterator());
  }

  /**
   * A sensible definition of {@link #isEmpty} as {@code !iterator().hasNext}. If you override