Implementation
List<DateRange> get lastThreeYears {
final yearStart = thisYearStart;
final yearEnd = thisYearEnd;
final thisYear = DateRange(yearStart, yearEnd);
final previousYear = thisYear.copyWith(
start: yearStart.copyWith(year: yearStart.year - 1),
end: yearEnd.copyWith(year: yearEnd.year - 1),
);
final twoYearsAgo = previousYear.copyWith(
start: previousYear.start.copyWith(year: previousYear.start.year - 1),
end: previousYear.end.copyWith(year: previousYear.end.year - 1),
);
return [thisYear, previousYear, twoYearsAgo];
}