python tornado UndefinedError：'static_url'未定义

Question

在我的foot.html上，我得到了

<img src="{{static_url('images/logo.png')}}" />

但它不起作用。

UndefinedError: 'static_url' is undefined

我在应用程序中的设置代码：

settings = dict(
 blog_title = u"F2E Community",
 template_path = os.path.join(os.path.dirname(__file__), "templates"),
 static_path = os.path.join(os.path.dirname(__file__), "static"),
 xsrf_cookies = True,
 cookie_secret = "cookie_secret_code",
 login_url = "/login",
 autoescape = None,
 jinja2 = Environment(loader = FileSystemLoader(os.path.join(os.path.dirname(__file__), "templates")), trim_blocks = True),
 reserved = ["user", "topic", "home", "setting", "forgot", "login", "logout", "register", "admin"],
 debug=True,
   )