Question about the frame without prev_frame

[TabGuigui]

Thanks for your excellent work.

I found that in Nuscenes planning task, the dataset initialization only considers the situation that if the number of future frames is not enough, and will give a fut_mask. However, if the key frame is the first frame in a scene and no prev_frame is in the log, the first frame will be copied as the prev frame. It's obvious that the model has to use one frame to predict the future without ego status. I wonder it is a reasonable setting?

Looking for your reply.