def GenerateCalendarDatesFieldValuesTuples(self):
    for date, (exception_type, _) in self.date_exceptions.items():
      yield (self.service_id, date, unicode(exception_type))
Generates tuples of calendar_dates.txt values. Yield zero tuples if
dataset/ETHPy150Open google/transitfeed/transitfeed/serviceperiod.py/ServicePeriod.GenerateCalendarDatesFieldValuesTuples