code: def backward(self, indexes, grad_outputs):
      return _RReLUGrad(self.y, self.r).apply(grad_outputs)
  
imports: import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import function_node
  from chainer.utils import argument
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the _RReLUGrad obj's underlying member method code with example usage: obj.backward(indexes, grad_outputs) and returns: _RReLUGrad