Symfony2 security functions in Twig? How to check the user's role?

I have Symfony 2.0.9 standard edition installed with JMSSecurityBundle. Just wondering what functions are available to me in a Twig template to deal with users?

Specifically I want check to see if a user has the role ROLE_ADMIN.

Any help?

Thanks


{% if is_granted('ROLE_ADMIN') %} ... {% endif %}