Pylons: __call__ and abort(), error code 500 instead of requested code

I'm trying to use pylons.controllers.utils.abort() function to terminate ap开发者_如何学Pythonplication and return corresponding code to the browser. But the only returning code is 500 Internal Server Error if calling from controller's method call(). For example

class ApiController(WSGIController):
    def __call__(self, environ, start_response):
        abort(411)

What should I change to get normal server response with code 411?

Edit: Nevermind, looks like abort() is not supposed to be used in the __call__() method.

abort() is not working properly there so I'm using this code now:

return HTTPBadRequest()(environ, start_response)