@web.request_filter
def auth_required(env, data, next_handler):
    if getattr(env, 'user', None) is None:
        return next_handler(env, data)
    response = web.Response(status=303)
    response.headers['Location'] = str(
                env.root.login.as_url.qs_set(next=env.request.path_info))
    return response
dataset/ETHPy150Open SmartTeleMax/iktomi/iktomi/auth.py/auth_required/operator `is not` -> `is`