code: def _RollGrad(op, grad):
      # The gradient is just the roll reversed
      shift = op.inputs[1]
      axis = op.inputs[2]
      roll_grad = manip_ops.roll(grad, -shift, axis)
      return roll_grad, None, None
  
label_desc: Use image node_id 1 for calling a global function with example usage: _RollGrad(op, grad) and returns: roll_grad,  None,  None