addMonths method
Adds the given number of months to this month. For instance:
<Mar 2015>.addMonths(4) --> Jul 2015
<Mar 2015>.addMonths(-3) --> Dec 2014
Implementation
CalendarMonth addMonths(int months) {
var newYear = year + (months / 12).floor();
var newMonth = month + months % 12;
if (newMonth > 12) {
newYear++;
newMonth -= 12;
}
return CalendarMonth(newYear, newMonth,
state: calendarState, startingWeekday: startingWeekday);
}