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