code: def forward(self, inputs):
      (x,) = inputs
      xp = backend.get_array_module(x)
      y = xp.zeros(self.out_shape, x.dtype)
      y_diag = y.diagonal(
          offset=self.offset, axis1=self.axis1, axis2=self.axis2
      )
      if xp is numpy:
          y_diag.setflags(write=True)
      y_diag[...] = x
      return (y,)
  
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 2 for calling the DiagonalGrad obj's underlying member method code with example usage: obj.forward(inputs) and returns: y