public static TimeSpan Quarter(Calendar calendar, int year, YearQuarter yearQuarter)
{
YearMonth[] quarterMonths = TimeTool.GetMonthsOfQuarter(yearQuarter);
TimeSpan duration = TimeSpec.NoDuration;
foreach (YearMonth quarterMonth in quarterMonths)
{
duration = duration.Add(Month(calendar, year, quarterMonth));
}
return(duration);
}