Ios SceneKit场景背景内容UIImage数组错误

我正在使用

SceneKit

为iOS开发一款游戏。当我想将skybox设置到场景时，我会收到一个错误：

var path = "skyboxes.scnassets/skybox"
self.scene!.background.contents = [
        UIImage(named: path+"_right.png"),
        UIImage(named: path+"_left.png"),
        UIImage(named: path+"_top.png"),
        UIImage(named: path+"_bottom.png"),
        UIImage(named: path+"_front.png"),
        UIImage(named: path+"_back.png"),
    ]

错误：无法将[UIImage？]类型的值分配给类型的值 随便

我试图将数组强制转换为

NSArray

或

AnyObject

数组，但这不起作用

---

有人能帮我吗？

内容属于
[AnyObject！]
类型；因此，以下措施应该有效：

scene!.background.contents =
[
    UIImage(named: path+"_right.png") as UIImage!              
    UIImage(named: path+"_left.png") as UIImage!,
    UIImage(named: path+"_top.png") as UIImage!,
    UIImage(named: path+"_bottom.png") as UIImage!,
    UIImage(named: path+"_front.png") as UIImage!,
    UIImage(named: path+"_back.png") as UIImage!,
]