code: def testSimpleParallelGPU(self):
      # tf.parallel_stack is only supported in graph mode.
      with ops.Graph().as_default():
          with test_util.device(use_gpu=True):
              for shape in (
                  (2,),
                  (3,),
                  (2, 3),
                  (3, 2),
                  (4, 3, 2),
                  (100, 24, 24, 3),
              ):
                  with self.subTest(shape=shape):
                      data = self.randn(shape, np.float32)
                      xs = list(map(constant_op.constant, data))
                      c = array_ops.parallel_stack(xs)
                      self.assertAllEqual(c, data)
  
imports: import numpy
  from tensorflow.python import tf2
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import constant_op
  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 array_ops_stack
  from tensorflow.python.ops import gen_array_ops
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 5 for calling the StackOpTest obj's underlying member method code with example usage: obj.testSimpleParallelGPU() without return types