Editing crud user (*, @, admin)

In CRUD Functions it is always found in UserController: or any Gii-generated crud model:




array('allow',  // allow all users to perform 'index' and 'view' actions

				'actions'=>array('index','view', 'admin','delete','create','update'),

				'users'=>array('*'),

			),

			array('allow', // allow authenticated user to perform 'create' and 'update' actions

				'actions'=>array('create','update'),

				'users'=>array('@'),

			),




Where does ‘$users’ array initialize? can I change *, @, admin to isAdmin(), isReg() and other extended CwebUser?