code: public ProjectCalendar addDefaultDerivedCalendar()
     {
        ProjectCalendar calendar = add();
  
        calendar.setWorkingDay(Day.SUNDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.MONDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.TUESDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.WEDNESDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.THURSDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.FRIDAY, DayType.DEFAULT);
        calendar.setWorkingDay(Day.SATURDAY, DayType.DEFAULT);
  
        return (calendar);
     }
docs: This is a convenience method to add a default derived
  calendar to the project.
  
  @return new ProjectCalendar instance