assert list contains elements of given class in Spock

I have a chain manager that contains some handlers. I would like to check if it has handlers of specific classes by default. How to do that?

def "contains few updaters on default"(){
    when:
        def manager = new UpdateManager();
    then:
        manager.getUpdaters().size() == 2;
        //how to check that the list contains elements of classes 
        //OneThingUpdater and OtherThingUpdater
}