docs: def to_url(request):
          """Serialize as a URL for a GET request."""
          scheme, netloc, path, query, fragment = urlsplit(to_utf8(request.url))
          query = parse_qs(query)
  
          for key, value in request.data_and_params.iteritems():
              query.setdefault(key, []).append(value)
  
          query = urllib.urlencode(query, True)
          return urlunsplit((scheme, netloc, path, query, fragment))