be bi-directional you can just run it in purely bi-directional mode so it's kind of trading a hybrid system and I think that was also a quite clever improvement they had the other thing I really like about this paper is it goes even farther in terms of elegance of kind of this shared framework for doing all tasks and all predictions so kind of one of the trends has been moving away from these custom architectures to the kind of shared pre-trained models that are a little bit more monolithic and can be used across a wide range of tasks with