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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def GenerateCalendarDatesFieldValuesTuples(self):
 """Generates tuples of calendar_dates.txt values. Yield zero tuples if this ServicePeriod should not be in calendar_dates.txt ."""

    for date, (exception_type, _) in self.date_exceptions.items():
      yield (self.service_id, date, unicode(exception_type))