code: def test_cpu(self):
      self._test(np)
  
file_path: chainerrl/tests/misc_tests/test_conjugate_gradient.py
imports: import unittest
  import chainer
  from chainer import testing
  from chainer.testing import condition
  import numpy
  import chainerrl
label_desc: Use image node_id 2 for calling the TestConjugateGradient obj's underlying member method code with example usage: obj.test_cpu() without return types