docs: def subsequent_calling_points(self):
          """
          A list of CallingPoint objects.
  
          This is the list of all subsequent calling points for the service,
          including all associated services if the service splits into multiple
          services.
          """
          calling_points = list()
          for cpl in self._subsequent_calling_point_lists:
              calling_points += cpl.calling_points
          return calling_points