Как сделать минимальный контроллер для Turbogears?

app/controllers/root.py

class Actor:
    def __call__(self, environ, context):
        status = '200 OK'
        response_body = 'ok'
        content_type = 'text/html'
        headers = [
            ('Content-Type', content_type),
            ('Content-Length', str(len(response_body.encode('utf-8')))),
            ('Access-Control-Allow-Origin', '*')
        ]
        response = context(status, headers)
        return [response_body.encode('utf-8')]

class RootController:
    def __call__(self, *args, **kwargs):
        response = Actor()
        response.status_code = 200
        response.content_type = 'plain/html'
        return response