code: def updatePSL(psl_file=PSLFILE):
      
      if requests is None:
          raise Exception("Please install python-requests http(s) library. $ sudo pip install requests")
  
  
      r = requests.get(PSLURL)
      if r.status_code != requests.codes.ok or len(r.content) == 0:
          raise Exception("Could not download PSL from " + PSLURL)
  
      lastmod = r.headers.get("last-modified", None)
      f = open(psl_file + ".swp", "wb")
      f.write(r.content)
      f.close()
  
      with open(psl_file + ".swp", "rb") as f:
          psl = PublicSuffixList(f)
  
      os.rename(psl_file + ".swp", psl_file)
      if lastmod:
          t = time.mktime(parsedate(lastmod))
          os.utime(psl_file, (t, t))
  
      print("PSL updated")
      if lastmod:
          print("last-modified: " + lastmod)
docs: Updates a local copy of PSL file
  
      :param psl_file: path for the file to store the list. Default: PSLFILE