public IEnumerable <Date> Filter(IPeriod period)
{
return(_daySelectors
.Select(daySelector => daySelector.PickDays(period.Days()))
.SelectMany(daySequence => _ordinals.Pick(daySequence)));
}
public IEnumerable <TPeriod> Pick(IEnumerable <TPeriod> periods) => _ordinal.Pick(periods);
public IEnumerable <Date> Filter(IPeriod period)
=> _ordinals.Pick(_weekDay
.PickDays(period.Days())
.Where(day => day.Day == _nth));