func (h holidaysUSNational) fixWeekend(in time.Time) time.Time {
	switch in.Weekday() {
	case time.Saturday:
		return in.Add(-1 * 24 * time.Hour)
	case time.Sunday:
		return in.Add(1 * 24 * time.Hour)
	default:
		return in
	}
}
func (h holidaysUSNational) fixWeekend(in time.Time) time.Time {
	switch in.Weekday() {
	case time.Saturday:
		return in.Add(-1 * 24 * time.Hour)
	case time.Sunday:
		return in.Add(1 * 24 * time.Hour)
	default:
		return in
	}
}
// If a holiday falls on a Saturday it is celebrated the preceding Friday;
// if a holiday falls on a Sunday it is celebrated the following Monday.