如何在变量更改时停止在DidMove上调用的SKAction

所以我在场景开始时加载并运行动画,但有一点我想停止动画。我确实理解为什么它不起作用,但我找不到解决它的方法。我尝试重写func update,但找不到更新函数的正确方法(如果有)。

override func didMove(to view: SKView) {
    loadAnimation(atlasName: "test")
    runAnimation(spriteName: "testImg", timeFrame: 0.08)    
}

func loadAnimation(atlasName : String) {
    let spriteAtlas = SKTextureAtlas(named: "\(atlasName)")
    
    for index in 1...spriteAtlas.textureNames.count{
        let image = String(format: "\(atlasName)%01d", index)
        atlasAnimation += [spriteAtlas.textureNamed(image)]
    }

}

func runAnimation(spriteName : String, timeFrame : Double) {
    let spriteNode = self.childNode(withName: "\(spriteName)")
    spriteNode?.name = "\(spriteName)"
    if (spriteNode != nil) {
        let animation = SKAction.animate(with: atlasAnimation, timePerFrame: timeFrame)
        let forever = SKAction.repeatForever(animation)
        spriteNode?.run(forever, withKey: "key")
        if spriteNode?.name == "whatever" {
            if i  < 18 {
                spriteNode?.removeAction(forKey: "key")
            }
        }
    }