code: def _update_day_dict(self, data_point, day_dict):
          
          for topic in ['Bounces', 'Complaints', 'DeliveryAttempts', 'Rejects']:
              day_dict[topic] = day_dict.get(topic, 0) + int(data_point[topic])
docs: Helper method for :meth:`_print_daily_stats`. Given a data point and
          the correct day dict, update attribs on the dict with the contents
          of the data point.
          
          :param dict data_point: The data point to add to the day's stats dict.
          :param dict day_dict: A stats-tracking dict for a 24 hour period.