code: def backward(self, indexes, grad_outputs):
      return Diagonal(self.offset, self.axis1, self.axis2).apply(
          grad_outputs
      )
  
file_path: chainer/chainer/functions/array/diagonal.py
imports: import numpy
  from chainer import backend
  from chainer import function_node
  from chainer.utils import type_check
label_desc: Use image node_id 3 for calling the DiagonalGrad obj's underlying member method code with example usage: obj.backward(indexes, grad_outputs) and returns: Diagonal