old_contents: import paddle.v2.dataset.common
  
  URL = 'http://ai.stanford.edu/%7Eamaas/data/sentiment/aclImdb_v1.tar.gz'
  MD5 = '7c2ac02c03563afcf9b574c7e56c153a'
  
  paddle.v2.dataset.common.download
  
new_contents: import paddle.v2.dataset.common
  import tarfile
  
  URL = 'http://ai.stanford.edu/%7Eamaas/data/sentiment/aclImdb_v1.tar.gz'
  MD5 = '7c2ac02c03563afcf9b574c7e56c153a'
  
  tarf = tarfile.open(paddle.v2.dataset.common.download(URL, 'imdb', MD5))
  
  tf = tarf.next()
  while tf != None:
      print tf.name
      tf = tarf.next()
  
subject: Add imdb_test.py