Month constructor
Month(
- int value
Creates a Month instance from an integer value (1-12).
Throws ArgumentError if the input is not between 1 and 12.
Implementation
factory Month(int value) {
if (value < 1 || value > 12) {
throw ArgumentError(
'Invalid month number: $value. Must be between 1 (January) and 12 (December).');
}
return values[value - 1];
}