srecord Seconds(double seconds) is Comparable<Seconds> {
  double seconds aka get aka getDouble() { ret seconds; }
  
  toString { ret formatDouble(seconds, 3) + " s"; }
  
  public int compareTo(Seconds s) {
    ret cmp(seconds, s.seconds);
  }
  
  Seconds div(double x) { ret Seconds(get()/x); }
  Seconds minus(Seconds x) { ret Seconds(get()-x!); }
}