: elementsToRetain;

    return self.elementSet().retainAll(collection);
  }

  /** An implementation of {@link Multiset#setCount(Object, int)}. */
  static <E extends @Nullable Object> int setCountImpl(
      Multiset<E> self, @ParametricNullness E element, int count) {
    checkNonnegative(count, "count");

    int oldCount = self.count(element);

    int delta = count - oldCount;
    if (delta > 0) {

            : elementsToRetain;

    return self.elementSet().retainAll(collection);
  }

  /** An implementation of {@link Multiset#setCount(Object, int)}. */
  static <E extends @Nullable Object> int setCountImpl(
      Multiset<E> self, @ParametricNullness E element, int count) {
    checkNonnegative(count, "count");

    int oldCount = self.count(element);

    int delta = count - oldCount;
    if (delta > 0) {