<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_running_races(self, year=None):
 """ Gets a running races for a given year. http://strava.github.io/api/v3/running_races/#list :param year: year for the races (default current) :return: An iterator of :class:`stravalib.model.RunningRace` objects. :rtype: :class:`BatchedResultsIterator` """

        if year is None:
            year = datetime.datetime.now().year
    
        params = {"year": year}

        result_fetcher = functools.partial(self.protocol.get,
                                           '/running_races',
                                           **params)

        return BatchedResultsIterator(entity=model.RunningRace, bind_client=self,
                                      result_fetcher=result_fetcher)