code: def _daily_periods(self, range_start, range_end):
          
          specific = set(self.exceptions.keys())
  
          return heapq.merge(self.exception_periods(range_start, range_end), *[
              sched.daily_periods(range_start=range_start, range_end=range_end, exclude_dates=specific)
              for sched in self._recurring_schedules
          ])
docs: Returns an iterator of Period tuples for every day this event is in effect, between range_start
          and range_end.