code: def test_batchify_stack():
      a = np.array([[1, 2, 3, 4], [5, 6, 7, 8]])
      b = np.array([[5, 6, 7, 8], [1, 2, 3, 4]])
      bf = mx.gluon.data.batchify.Stack()
      bf_handle = bf.__mx_handle__()
      c = bf([a, b])
      d = bf_handle([a, b])
      assert c.shape == d.shape
      assert mx.test_utils.almost_equal(c.asnumpy(), d.asnumpy())
      assert mx.test_utils.almost_equal(c.asnumpy(), np.stack((a, b)))
  
imports: import os
  import tarfile
  import tempfile
  import unittest
  import mxnet
  import numpy
  import random
  from mxnet import gluon
  import platform
  from mxnet.gluon.data import DataLoader
  import mxnet.ndarray
  from mxnet import context
  from mxnet.gluon.data.dataset import Dataset
  from mxnet.gluon.data.dataset import ArrayDataset
  import pytest
label_desc: Use image node_id 34 for calling a global function with example usage: test_batchify_stack() without return types