I have the following code: next_job = yield self.scrapers_coll.find_one_and_update( {"state": "enqueued"}, { "$set": { "startTime": time.time(), } }, sort=[("createdOn", pymongo.ASCENDING)] ) This gives me a `TypeError: list indices must be integers or slices, not str`. From going through the source code it looks like TxMongo wants a different format than PyMongo. How do I specify the sort order in this case?