parse static method
Implementation
static ByDay parse(String byDayString) {
return ByDay(
preCount: int.tryParse(byDayString.length > 2 ? byDayString.substring(0,byDayString.length-2) : ''),
day: Days.values.firstWhere((e)=>e.name.toUpperCase() == byDayString.substring(byDayString.length-2,byDayString.length).toUpperCase())
);
}