Symfony4 - 从控制器访问sevices.yaml

Question

I am starting a symfony4 project, and I learned the "parameters.yaml" is now "sevice.yaml".

I setted some variables inside like:

parameters:
    smugmug.oauth_token: 'XXX'
    smugmug.oauth_token_secret: 'XXX'

And i try to access it from my controller like:

    dump($this->container->get('smugmug.oauth_token'));

But I have an error...

How does this new way of storing global variables is working?