static <A, B> L<Map<B, A>> mapToTwoElementMaps(B keyKey, B valueKey, Map<A> map) {
  new L<Map<B, A>> l;
  if (map != null) for (Map.Entry<A, A> e : map.entrySet())
    l.add(litorderedmap(keyKey, e.getKey(), valueKey, e.getValue()));
  ret l;
}