code: def forward_cpu(self, inputs):
      self.retain_inputs((0, 1))
      y, gy = inputs
      one = y.dtype.type(1)
      return (utils.force_array(gy * (one - y * y)),)
  
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
  import chainerx
label_desc: Use image node_id 2 for calling the TanhGrad obj's underlying member method code with example usage: obj.forward_cpu(inputs) and returns: utils