docs: def redirect(url, code=None):
      """ Aborts execution and causes a 303 or 302 redirect, depending on
          the HTTP protocol version. """
      if not code:
          code = 303 if request.get('SERVER_PROTOCOL') == "HTTP/1.1" else 302
      res = response.copy(cls=HTTPResponse)
      res.status = code
      res.body = ""
      res.set_header('Location', urljoin(request.url, url))
      raise res