Can I have a computed property from an injected service?

I have an isAuthenticated property in a service that is currently injected on my application route, how can I have a computed property from the injected service in my route?

export default Ember.Route.extend({
    session : Ember.inject.service('market-session'),
    isUser : Ember.computed.oneWay('session.IsAuthenticated'),
}

Is this possible?