*/

  private static <K, V> SortedMap<K, V> newModifiableDelegate(Comparator<? super K> comparator) {
    return newTreeMap(nullAccepting(comparator));
  }

  private static <E> Comparator<@Nullable E> nullAccepting(Comparator<E> comparator) {
    return Ordering.from(comparator).nullsFirst();
  }