is from its neighbors and so you can train this policy by just by popping in gradient of the cost through the entire system all the way down to the policy Network if you do this it doesn't work because what happens is the system gets into regions of the space where the foreign model does a really bad job at predicting what happens to have low cost okay so the car can it goes off the road or something like that and this can be due also to flaws in the in a cost function but but basically it doesn't do what you want so what you have to do is