code: def GetServicePeriodsActiveEachDate(self, date_start, date_end):
      
      date_it = date_start
      one_day = datetime.timedelta(days=1)
      date_service_period_list = []
      while date_it < date_end:
        periods_today = []
        date_it_string = date_it.strftime("%Y%m%d")
        for service in self.GetServicePeriodList():
          if service.IsActiveOn(date_it_string, date_it):
            periods_today.append(service)
        date_service_period_list.append((date_it, periods_today))
        date_it += one_day
      return date_service_period_list
docs: Return a list of tuples (date, [period1, period2, ...]).
  
      For each date in the range [date_start, date_end) make list of each
      ServicePeriod object which is active.
  
      Args:
        date_start: The first date in the list, a date object
        date_end: The first date after the list, a date object
  
      Returns:
        A list of tuples. Each tuple contains a date object and a list of zero or
        more ServicePeriod objects.