know now these models are like really really you know went from like in the last two or three years because of leveraging unsupervised pre training and kind of scalable methods to really make quite a lot of progress in this space very quickly so this is Bert so what Bert does is it basically finds a very great way to hybridize a language model objective with kind of the importance of like bidirectionality so again you know by default we have this like left/right auto regressive factorization where we say given the