code: def related(self):
          
          if self._related is None:
              if self.athlete_count - 1 > 0:
                  self.assert_bind_client()
                  self._related = self.bind_client.get_related_activities(self.id)
              else:
                  self._related = []
          return self._related
docs: Iterator of :class:`stravalib.model.Activty` objects for activities matched as
          with this activity.