<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _calc_daystamps(self, st_time, end_time):
 """Calculate days of the year between start time and end time. Use this method only when start time month is before end time month. """

        start_doy = sum(self._num_of_days_each_month[:st_time.month-1]) + st_time.day
        end_doy = sum(self._num_of_days_each_month[:end_time.month-1]) + end_time.day + 1
        return list(range(start_doy, end_doy))