def requires_authentication(method):
    """
    self points to a SheisseController instance instead of the decorator function.
    """
    def wrapper(self, *args, **kwargs):
        if self._requires_authentication == True and self._authenticated == False:
            return response('403 Forbidden or whatever')

        return method(self, *args, **kwargs)
    return wrapper

class SheisseController:
  @requires_authentication
  def index(self):