code: def download_imdb(data_dir="/tmp/data"):
      """
      Download and extract the IMDB dataset
      """
      # Large Movie Review Dataset from http://ai.stanford.edu/~amaas/data/sentiment/
      # Note this dataset is copyright to Andrew Maas and Stanford AI Lab
      # @InProceedings{maas-EtAl:2011:ACL-HLT2011,
      #   author    = {Maas, Andrew L.  and  Daly, Raymond E.  and  Pham, Peter T.  and  Huang, Dan  and  Ng, Andrew Y.  and  Potts, Christopher},
      #   title     = {Learning Word Vectors for Sentiment Analysis},
      #   booktitle = {Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies},
      #   month     = {June},
      #   year      = {2011},
      #   address   = {Portland, Oregon, USA},
      #   publisher = {Association for Computational Linguistics},
      #   pages     = {142--150},
      #   url       = {http://www.aclweb.org/anthology/P11-1015}
      # }
      url = "https://aws-ml-platform-datasets.s3.amazonaws.com/imdb/aclImdb_v1.tar.gz"
      sha1 = "01ada507287d82875905620988597833ad4e0903"
      if not os.path.exists(data_dir):
          os.makedirs(data_dir)
      file_path = os.path.join(data_dir, "aclImdb_v1.tar.gz")
      if not os.path.isfile(file_path):
          file_path = gluon.utils.download(
              url, data_dir, sha1_hash=sha1
          )
      with tarfile.open(file_path, "r") as f:
          f.extractall(data_dir)
  
imports: import collections
  import os
  import random
  import sys
  import tarfile
  import mxnet
  from mxnet import nd, gluon
  from mxnet.contrib import text
  from mxnet.gluon import nn, rnn
  from mxnet.gluon.contrib.estimator import estimator
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: download_imdb(data_dir) without return types