compareTo method
Implementation
@override
int compareTo(covariant Contact other) {
// 1ยบ comparison
final int comparison1 = name.compareTo(other.name);
if (comparison1 != 0) return comparison1;
// Last comparison
final DateTime nonNullBirthday = birthday ?? DateTime(0);
final DateTime nonNullOtherBirthday = other.birthday ?? DateTime(0);
final int comparison3 = nonNullBirthday.compareTo(nonNullOtherBirthday);
return comparison3;
}