import java.util.Collection;

public final class addAllImpl {
  private static abstract class Multiset<K> extends Collection<K> { }
  static <E> boolean addAllImpl(
      Multiset<E> self, Collection<?> elements) {
    return addAllImpl(self, (Multiset) elements);
  }

  private static <E> boolean addAllImpl(
      Multiset<E> self, Multiset<E> elements) {
  }
}