static Comparator<S> howLongAgo_comparator() {
  ret makeComparator(func(S a, S b) -> int {
    long timeB = howLongAgo_toMS(b), timeA = howLongAgo_toMS(a);
    int result = cmp(timeB, timeA);
    ifdef howLongAgo_comparator_debug
      print("howLongAgo: " + a + " " + smallerGreaterEqualSign(-result) + " " + b);
    endifdef
    ret result;
  });
}