code: @Override
    public int compareTo(Timespan timespan)
    {
      if(timespan.getTimeUnit() == getTimeUnit())
        return LangUtils.compare(getDuration(), timespan.getDuration());
      else
        return LangUtils.compare(getDurationInMilliseconds(), timespan.getDurationInMilliseconds());
    }
docs: Compares 2 timespan. Based on duration in milliseconds.
  
  @param timespan
  @return 0 if same duration in milliseconds,