function compareMonth(obj) {
  obj.weeks.forEach((week, weeki) => {
    week.days.forEach((day, dayi) => {
      // @ts-expect-error since we are converting Date to ISO string, but that's okay for our test Date comparisons
      // eslint-disable-next-line no-param-reassign
      obj.weeks[weeki].days[dayi].date = obj.weeks[weeki].days[dayi].date.toISOString();
    });
  });
  return obj;
}
@param {import('../../types/day.js').Month} obj