code: def test_to_cpu_to_gpu_cpu(self):
      self.check_to_cpu_to_gpu(self.c, self.h)
  
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 6 for calling the TestZoneoutToCPUToGPU obj's underlying member method code with example usage: obj.test_to_cpu_to_gpu_cpu() without return types