code: public long toLong() {
      int workingDays = days;
      int workingHours = hours;
      if (hours >= hoursInDay) {
        int nbAdditionalDays = hours / hoursInDay;
        workingDays += nbAdditionalDays;
        workingHours = hours - (nbAdditionalDays * hoursInDay);
      }
      return 1L * workingDays * DAY_POSITION_IN_LONG + workingHours * HOUR_POSITION_IN_LONG + minutes * MINUTE_POSITION_IN_LONG;
    }
docs: Return the duration using the following format DDHHMM, where DD is the number of days, HH is the number of months, and MM the number of minutes.
  For instance, 3 days and 4 hours will return 030400 (if hoursIndDay is 8).