next method

SolarMonth next(
  1. int months
)

Implementation

SolarMonth next(int months) {
  int n = months < 0 ? -1 : 1;
  int m = months.abs();
  int y = _year + (m / 12).floor() * n;
  m = _month + m % 12 * n;
  if (m > 12) {
    m -= 12;
    y++;
  } else if (m < 1) {
    m += 12;
    y--;
  }
  return SolarMonth.fromYm(y, m);
}