code: def forward_cpu(self, inputs):
      (gy,) = inputs
      gy = np.where(self.y >= 0, gy, gy * self.r)
      return (gy,)
  
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 2 for calling the _RReLUGrad obj's underlying member method code with example usage: obj.forward_cpu(inputs) and returns: gy