public long convertToMillis(Duration duration) {
   long millis = duration.getMillis();
   millis += duration.getSeconds() * secondInMillis;
   millis += duration.getMinutes() * minuteInMillis;
   millis += duration.getHours() * hourInMillis;
   if (duration.isBusinessTime()) {
     millis += duration.getDays() * businessDayInMillis;
     millis += duration.getWeeks() * businessWeekInMillis;
     millis += duration.getMonths() * businessMonthInMillis;
     millis += duration.getYears() * businessYearInMillis;
   } else {
     millis += duration.getDays() * dayInMillis;
     millis += duration.getWeeks() * weekInMillis;
     millis += duration.getMonths() * monthInMillis;
     millis += duration.getYears() * yearInMillis;
   }
   return millis;
 }