def _frequencies(self, trip_id):
        if trip_id not in self.freq_cache:
            query = """select start_time, end_time, headway_secs
            from frequencies where trip_id=:trip_id and
            _feed=:_feed order by start_time asc"""
            filter = {'trip_id': trip_id, '_feed': self.provider.feed_id}
            cur = self.provider.conn.cursor()
            self.freq_cache[trip_id] = cur.execute(query, filter).fetchall()
        return self.freq_cache[trip_id]
dataset/ETHPy150Open spaceboats/busbus/busbus/provider/gtfs.py/GTFSArrivalGenerator._frequencies/original