code: def download(directory, filename):
      """Download (and unzip) a file from the MNIST dataset if not already done."""
      filepath = os.path.join(directory, filename)
      if tf.io.gfile.exists(filepath):
          return filepath
      if not tf.io.gfile.exists(directory):
          tf.io.gfile.makedirs(directory)
      # CVDF mirror of http://yann.lecun.com/exdb/mnist/
      url = (
          "https://storage.googleapis.com/cvdf-datasets/mnist/"
          + filename
          + ".gz"
      )
      _, zipped_filepath = tempfile.mkstemp(suffix=".gz")
      print("Downloading %s to %s" % (url, zipped_filepath))
      urllib.request.urlretrieve(url, zipped_filepath)
      with gzip.open(zipped_filepath, "rb") as f_in, tf.io.gfile.Gfile(
          filepath, "wb"
      ) as f_out:
          shutil.copyfileobj(f_in, f_out)
      os.remove(zipped_filepath)
      return filepath
  
file_path: tensorflow-upstream/tensorflow/lite/tutorials/dataset.py
imports: import gzip
  import os
  import shutil
  import tempfile
  import urllib
  import numpy
  import tensorflow
label_desc: Use image node_id 4 for calling a global function with example usage: download(directory, filename) and returns: filepath, filepath