code: def test_forward_cpu(self):
      self.f.add_hook(self.h)
      self.f(chainer.Variable(self.x), chainer.Variable(self.x))
      # In some environments, shape is long.
      expect = r"""^function\tDummyFunction
  input data
  <variable at 0x[0-9a-f]+>
  - device: CPU
  - backend: <(type|class) 'numpy.ndarray'>
  - shape: \(3L?, 5L?\)
  - dtype: float32
  - statistics: mean=[0-9.\-e]+, std=[0-9.\-e]+
  - grad: None
  <variable at 0x[0-9a-f]+>
  - device: CPU
  - backend: <(type|class) 'numpy.ndarray'>
  - shape: \(3L?, 5L?\)
  - dtype: float32
  - statistics: mean=[0-9.\-e]+, std=[0-9.\-e]+
  - grad: None$
  """
      actual = self.io.getvalue()
      self.assertTrue(re.match(expect, actual), actual)
  
imports: import re
  import unittest
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import function_hooks
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling the TestPrintHookToFunction obj's underlying member method code with example usage: obj.test_forward_cpu() without return types