docs: def send_request(self, url):
          """ Send a request to given url. """
          while True:
              try:
                  return urllib.request.urlopen(url)
              except urllib.error.HTTPError as e:
                  raise serror(
                      "Request `%s` failed (%s:%s)." %
                      (url, e.__class__.__name__, e.code))
              except Exception as e:
                  choice = input(serror(
                      "Error occured: %s - Retry? [yN]" % type(e)))
                  if choice.strip().lower() != "y":
                      raise serror(e)