} // Halfyear
// ----------------------------------------------------------------------
public static TimeSpan Halfyear(Calendar calendar, int year, YearHalfyear yearHalfyear)
{
YearMonth[] halfyearMonths = TimeTool.GetMonthsOfHalfyear(yearHalfyear);
TimeSpan duration = TimeSpec.NoDuration;
foreach (YearMonth halfyearMonth in halfyearMonths)
{
duration = duration.Add(Month(calendar, year, halfyearMonth));
}
return(duration);
} // Halfyear