code: def test_cpu_and_gpu_devices():
      device = C.cpu()
      assert device.type() == C.device.DeviceKind.CPU
      assert device.id() == 0
      for i in range(len(C.device.all_devices()) - 1):
          device = C.gpu(i)
          assert device.type() == C.device.DeviceKind.GPU
          assert device.id() == i
  
imports: import numpy
  import pytest
  import cntk
  from multiprocessing import Process, Queue
label_desc: Use image node_id 5 for calling a global function with example usage: test_cpu_and_gpu_devices() without return types