private Integer twelveHourStyle(Integer aHour){
    Integer result = aHour;
    if(aHour != null){
      if (aHour == 0) {
        result = 12; //eg 12:30 am
      }
      else if (aHour > 12){
        result = aHour - 12; //eg 14:00 -> 2:00
      }
    }
    return result;
  }