code: def download_diffs(queue):
      
      while True:
          options, signature_type, localver, remotever = queue.get()
          for num in range(int(localver), int(remotever) + 1):
              sig_diff = '%s-%d' % (signature_type, num)
              filename = os.path.join(options.mirrordir, '%s.cdiff' % sig_diff)
              if not os.path.exists(filename):
                  update_diff(options, sig_diff)
          queue.task_done()
docs: Download the cdiff files