Method rollback

xarray/coding/cftime_offsets.py:579–584

Roll date backward to nearest start of year

(self, date)

            return date + YearBegin(month=self.month)

    def rollback(self, date):
        """Roll date backward to nearest start of year"""
        if self.onOffset(date):
            return date
        else:
            return date - YearBegin(month=self.month)


class YearEnd(YearOffset):