checkNotNull(elements);
    Comparator<?> comparator2;
    if (elements instanceof SortedSet) {
      comparator2 = comparator((SortedSet<?>) elements);
    } else if (elements instanceof SortedIterable) {
      comparator2 = ((SortedIterable<?>) elements).comparator();
    } else {
      return false;
    }
    return comparator.equals(comparator2);
  }

  @SuppressWarnings("unchecked")