code: def get_activities(self, before=None, after=None, limit=None):
          
  
          if before:
              before = self._utc_datetime_to_epoch(before)
  
          if after:
              after = self._utc_datetime_to_epoch(after)
  
          params = dict(before=before, after=after)
          result_fetcher = functools.partial(self.protocol.get,
                                             '/athlete/activities',
                                             **params)
  
          return BatchedResultsIterator(entity=model.Activity,
                                        bind_client=self,
                                        result_fetcher=result_fetcher,
                                        limit=limit)
docs: Get activities for authenticated user sorted by newest first.
  
          http://strava.github.io/api/v3/activities/
  
  
          :param before: Result will start with activities whose start date is
                         before specified date. (UTC)
          :type before: datetime.datetime or str or None
  
          :param after: Result will start with activities whose start date is after
                        specified value. (UTC)
          :type after: datetime.datetime or str or None
  
          :param limit: How many maximum activities to return.
          :type limit: int or None
  
          :return: An iterator of :class:`stravalib.model.Activity` objects.
          :rtype: :class:`BatchedResultsIterator`