code: def backward(self, indexes, grad_outputs):
      return (
          chainer.functions.where(
              utils.force_array(self.cond),
              grad_outputs[0],
              grad_outputs[1],
          ),
      )
  
file_path: chainer/chainer/functions/math/maximum.py
imports: import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import function_node
  from chainer import utils
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the MaximumGrad obj's underlying member method code with example usage: obj.backward(indexes, grad_outputs) and returns: chainer