}

  public static <K, V> ImmutableSortedMap<K, V> copyOfSorted(SortedMap<K, ? extends V> map) {
    // If map has a null comparator, the keys should have a natural ordering,
    // even though K doesn't explicitly implement Comparable.
    @SuppressWarnings("unchecked")
    Comparator<? super K> comparator =
        (map.comparator() == null) ? (Comparator<? super K>) NATURAL_ORDER : map.comparator();