code: def check_to_cpu(self, h):
      self.link.set_state(h)
      with testing.assert_warns(DeprecationWarning):
          self.link.to_cpu()
      self.assertIsInstance(self.link.h.data, self.link.xp.ndarray)
      with testing.assert_warns(DeprecationWarning):
          self.link.to_cpu()
      self.assertIsInstance(self.link.h.data, self.link.xp.ndarray)
  
imports: import unittest
  import numpy
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling the TestGRUToCPUToGPU obj's underlying member method code with example usage: obj.check_to_cpu(h) without return types