code: def _use_default_device(queue):
      # use_default_device needs to be tested in isolation
      # in a freshly created process environment.
      device = C.use_default_device()
      if device.type() != C.device.DeviceKind.GPU:
          queue.put(not is_locked(device))
      else:
          queue.put(is_locked(device))
  
imports: import numpy
  import pytest
  import cntk
  from multiprocessing import Process, Queue
label_desc: Use image node_id 8 for calling a global function with example usage: _use_default_device(queue) without return types