docs: def lookup_ids(handles):
      """ Fetch the twitter ids of each screen_name. """
      ids = set()
      for handle_list in [handles[100 * i:100 * i + 100] for i in range(len(handles))]:
          if len(handle_list) > 0:
              while True:
                  r = twapi.request('users/lookup', {'screen_name': ','.join(handle_list)})
                  if r.status_code in [88, 130, 420, 429]:  # rate limit
                      sys.stderr.write('Sleeping off rate limit for %s: %s\n' % (str(handle_list), r.text))
                      time.sleep(300)
                  elif r.status_code == 200:
                      for item in r.get_iterator():
                          ids.add(item['id_str'])
                      break
                  else:
                      sys.stderr.write('Error: %s\nSkipping %s...\n' % (str(handle_list), r.text))
                      break
  
      return ids