code: def _retrieve_mnist_test():
      urls = [
          "http://yann.lecun.com/exdb/mnist/t10k-images-idx3-ubyte.gz",
          "http://yann.lecun.com/exdb/mnist/t10k-labels-idx1-ubyte.gz",
      ]
      return _retrieve_mnist("test.npz", urls)
  
file_path: chainer/chainer/datasets/mnist.py
imports: import os
  import numpy
  import chainer
  from chainer.dataset import download
  from chainer.datasets._mnist_helper import make_npz
  from chainer.datasets._mnist_helper import preprocess_mnist
label_desc: Use image node_id 3 for calling a global function with example usage: _retrieve_mnist_test() and returns: _retrieve_mnist