def _enter_list_mode(self, operator):
        if self._list_mode:
            return
        if self._page_iter:
            raise RuntimeError("Cannot use %s when results have been iterated." % operator)
        if self.response_future.has_more_pages:
            log.warning("Using %s on paged results causes entire result set to be materialized.", operator)
        self._fetch_all()  # done regardless of paging status in case the row factory produces a generator
        self._list_mode = True
dataset/ETHPy150Open datastax/python-driver/cassandra/cluster.py/ResultSet._enter_list_mode/original