static <A, B> MultiMap<A, B> clonetailMultiMap(MultiMap<A, B> mm, A key, bool inclusive) {
  if (mm == null) null;
  var mm2 = similarEmptyMultiMap(mm);
  for (e : entrySet(castMultiMapToNavigableMap(mm).tailMap(key, inclusive)))
    mm2.data.put(e.getKey(), e.getValue());
  ret mm2;
}