MonthRange constructor
Implementation
factory MonthRange(DateTime start, DateTime stop, [int stepInMonths = 1]) {
if (stepInMonths <= 0) {
throw ArgumentError.value(
stepInMonths, 'stepInMonths', 'Must be greater than 0');
}
if (stop.isBefore(start)) stepInMonths = -stepInMonths;
return MonthRange._(start, stop, stepInMonths);
}