Generating a random SKNode position without it being equal to others ones

I have an array of moving SKNodes, and I want to create one that does not have the same position of any others, how? I have some code that didn't actually work. You can check it below:

extension CGPoint {

static func getRandom(inside scene: SKScene, andArray array: [SKSpriteNode]) -> CGPoint {
    let x: CGFloat = getRandomX(inside: scene, andArray: array)
    let y: CGFloat = getRandomY(inside: scene, andArray: array)
    let i = getRandomSign()
    return Point(x * i, y * i)
}

private static func getRandomX(inside scene: SKScene, andArray array: [SKSpriteNode]) -> CGFloat {
    var val = CGFloat(arc4random() % UInt32(scene.frame.width/2))

    for node in array {
        if val == node.position.x {
            val = getRandomX(inside: scene, andArray: array)
        }
    }
    return val
}

private static func getRandomY(inside scene: SKScene, andArray array: [SKSpriteNode]) -> CGFloat {
    var val = CGFloat(arc4random() % UInt32(scene.frame.height/2))

    for node in array {
        if val == node.position.y {
            val = getRandomY(inside: scene, andArray: array)
        }
    }
    return val
}

private static func getRandomSign() -> CGFloat {
    let val = arc4random()
    if val % 2 == 0 {
        return -1
    } else {
        return 1
    }
}
}

The CGPoint.getRandom(....) gets called when adding a node, in the SKScene.