Swift Casting in Callback Parameter

param.swift

// How do you cast SKNode to Flag : SKNode in parameter definition?

scene.enumerateChildNodesWithName("flag") {
    node as Flag, stop in
        node.methodAvailableToFlagObject()
}

// I'm trying to avoid having to do this:

scene.enumerateChildNodesWithName("flag") {
    node, stop in 
        let realNode = node as Flag
        realNode.methodAvailableToFlagObject()
}