code: def GenerateDateTripsDeparturesList(self, date_start, date_end):
      
  
      service_id_to_trips = defaultdict(lambda: 0)
      service_id_to_departures = defaultdict(lambda: 0)
      for trip in self.GetTripList():
        headway_start_times = trip.GetFrequencyStartTimes()
        if headway_start_times:
          trip_runs = len(headway_start_times)
        else:
          trip_runs = 1
  
        service_id_to_trips[trip.service_id] += trip_runs
        service_id_to_departures[trip.service_id] += (
            (trip.GetCountStopTimes() - 1) * trip_runs)
  
      date_services = self.GetServicePeriodsActiveEachDate(date_start, date_end)
      date_trips = []
  
      for date, services in date_services:
        day_trips = sum(service_id_to_trips[s.service_id] for s in services)
        day_departures = sum(
            service_id_to_departures[s.service_id] for s in services)
        date_trips.append((date, day_trips, day_departures))
      return date_trips
docs: Return a list of (date object, number of trips, number of departures).
  
      The list is generated for dates in the range [date_start, date_end).
  
      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 (date object, number of trips, number of departures) tuples