code: def rescale_grad_hook(module, idx, grad):
      lang_bsz = module.last_lang_bszs[idx]
      if lang_bsz > 0:
          return grad * float(module.last_bsz) / float(lang_bsz)
      return grad
  
imports: import torch
  import torch.nn
  from fairseq.models import FairseqEncoder, FairseqIncrementalDecoder
  from pytorch_translate import utils
  from pytorch_translate.data import data
label_desc: Use image node_id 1 for calling a global function with example usage: rescale_grad_hook(module, idx, grad) and returns: grad, unknown