symfony - How to have multiple authenticator in Symfony2 Security simple_preauth firewall -

we building symfony website expose rest api mobile app authentication token, autorize developer consume api, feature, using simple_preauth firewall authenticator, works fine. firewall configuration :

firewalls:     app_authenticated:         pattern: ^/api         context: app         stateless: true         simple_preauth:             authenticator: api_key_authenticator 

but our mobile app offer end-user login , need user's session stateless, means, logged-in user's token has supplied along developer's token, how implement multimple authenticator under simple_preauth firewall index?

i tried supplying [api_key_authenticator, api_key_authenticator2] 2 authenticators simple_preauth.authenticator requires value scalar, not array. around ?