the code generates following error$-$ Error encountered during training$/$evaluation letter counting. Please check code.

Traceback $($most recent call last$)$:

File $"/$autograder$/$source$/$code$/$wrapper$.$py$",$ line $152,$ in

lc$\_$model $=$ train$\_$lc$\_$classifier$($args$,$ train$\_$lc$\_$bundles, dev$\_$lc$\_$bundles$)$

File $"/$autograder$/$source$/$code$/$transformer$.$py$",$ line $156,$ in train$\_$classifier

output$\_$batch$\_$expanded $=$ output$\_$batch.unsqueeze$(1).$expand$(-1,$ seq$\_$length$)$ # Expand the output batch

RuntimeError: expand$($torch$.$LongTensor$\{[32,1,20]\},$ size$=[-1,20])$: the number of sizes provided $(2)$ must be greater or equal to the number of dimensions in the tensor $(3)$

provide updated code