code: def check_exist_or_download(url):
      """download data into tmp"""
      name = url.rsplit("/", 1)[-1]
      filename = os.path.join(download_dir, name)
      if not os.path.isfile(filename):
          print("Downloading %s" % url)
          urllib.request.urlretrieve(url, filename)
      return filename
  
file_path: singa/examples/qabot/qabot_data.py
imports: import numpy
  import random
  import os
  import urllib
label_desc: Use image node_id 1 for calling a global function with example usage: check_exist_or_download(url) and returns: filename