lookup method
Implementation
@override
CalendarValueLookup lookup(int year, [int? month, int? day]) {
DateTime current = _convertNecessarry(date, year, month, day);
if (current.isAtSameMomentAs(DateTime(year, month ?? 1, day ?? 1))) {
return CalendarValueLookup.selected;
}
return CalendarValueLookup.none;
}