code: def forward_cpu(self, x):
      self.retain_outputs((0,))
      return (utils.force_array(numpy.exp(x[0])),)
  
imports: import math
  import numpy
  from chainer import backend
  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 4 for calling the Exp obj's underlying member method code with example usage: obj.forward_cpu(x) and returns: utils