code: def test_forward_cpu(self):
      self.check_forward(self.x, self.t)
  
file_path: chainer/tests/chainer_tests/links_tests/loss_tests/test_black_out.py
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 4 for calling the TestBlackOut obj's underlying member method code with example usage: obj.test_forward_cpu() without return types