code: def test_to_cpu(self):
      f = copy.deepcopy(self.link)._func
      with testing.assert_warns(DeprecationWarning):
          self.link.to_gpu()
      with testing.assert_warns(DeprecationWarning):
          self.link.to_cpu()
      g = self.link._func
  
      self.assertTrue((f.begins == g.begins).all())
      self.assertTrue((f.paths == g.paths).all())
      self.assertTrue((f.codes == g.codes).all())
  
imports: import copy
  import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import condition
label_desc: Use image node_id 10 for calling the TestBinaryHierarchicalSoftmax obj's underlying member method code with example usage: obj.test_to_cpu() without return types