code: def download_news20(dest_dir):
      news20 = "20news-18828.tar.gz"
      news20_path = base.maybe_download(news20, dest_dir, NEWS20_URL)
      tar = tarfile.open(news20_path, "r:gz")
      news20_dir = os.path.join(dest_dir, "20news-18828")
      if not os.path.exists(news20_dir):
          print("Extracting %s to %s" % (news20_path, news20_dir))
          tar.extractall(dest_dir)
          tar.close()
  
file_path: analytics-zoo/pyzoo/zoo/examples/textclassification/news20.py
imports: import tarfile
  import zipfile
  from bigdl.dataset import base
  from bigdl.util.common import *
label_desc: Use image node_id 3 for calling a global function with example usage: download_news20(dest_dir) without return types