code: public static <T> Comparator<T> safeComparator(Comparator<? super T> baseComp, NullOrdering nullOrd) {
          return nullOrd.toComparator(baseComp);
      }
docs: Retrieves a <i>safe</i> comparator, which can handle <code>null</code> element values. Whether <code>null</code>
  values are smaller or bigger than regular values is controlled by the {@link NullOrdering} parameter.
  
  @param <T>
  original element class.
  @param baseComp
  the basic comparator.
  @param nullOrd
  the ordering policy for <code>null</code> values.
  
  @return a safe comparator using the specified underlying comparator.