code: def backward(ctx, grad_output):
      grad_output = grad_output.view(-1, 1, 1, 1).to(ctx.grads)
      return ctx.grads.mul(grad_output), None, None, None, None, None
  
imports: import numpy
  import torch
  from torch.autograd import Function, Variable
  from torch.nn import Module
label_desc: Use image node_id 2 for calling the _RNNT obj's underlying member method code with example usage: obj.backward(ctx, grad_output) and returns: ctx,  None,  None,  None,  None,  None