code: public static <E> ImmutableSortedMultiset<E> copyOf(
        Comparator<? super E> comparator, Iterator<? extends E> elements) {
      checkNotNull(comparator);
      return new Builder<E>(comparator).addAll(elements).build();
    }
docs: Returns an immutable sorted multiset containing the given elements sorted by the given {@code
  Comparator}.
  
  @throws NullPointerException if {@code comparator} or any of {@code elements} is null