def require_setting(self, name, feature="this feature"):
        if not self.application.settings.get(name):
            raise Exception("You must define the '%s' setting in your "
                            "application to use %s" % (name, feature))
Raises an exception if the given app setting is not defined.
dataset/ETHPy150Open RobotWebTools/rosbridge_suite/rosbridge_server/src/tornado/web.py/RequestHandler.require_setting