code: def testColocation(self):
      gpu_dev = test.gpu_device_name()
  
      with ops.Graph().as_default() as G:
          with ops.device("/cpu:0"):
              x = array_ops.placeholder(dtypes.float32)
              v = 2.0 * (array_ops.zeros([128, 128]) + x)
          with ops.device(gpu_dev):
              stager = data_flow_ops.StagingArea([dtypes.float32])
              y = stager.put([v])
              expected_name = (
                  gpu_dev if "gpu" not in gpu_dev else "/device:GPU:0"
              )
              self.assertEqual(y.device, expected_name)
          with ops.device("/cpu:0"):
              x = stager.get()[0]
              self.assertEqual(x.device, "/device:CPU:0")
  
      G.finalize()
  
imports: import queue
  import threading
  import numpy
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import data_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the StageTest obj's underlying member method code with example usage: obj.testColocation() without return types