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)