无法将类型"NSMutableArray"的值转换为预期的参数类型"[SKAction]"

我检查了我的旧游戏(由SpriteKit制造)，并想在Swift 2.0中进行更新.当我尝试修复它时，Xcode发现一个错误.

I checked my old game (made in SpriteKit) and I want to update it in Swift 2.0. When I tried to fix it, Xcode found an errors.

错误是:无法将类型'NSMutableArray'的值转换为预期的参数类型'[SKAction]'

在代码中:

torpedo.runAction(SKAction.sequence(actionArray))

功能

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

self.runAction(SKAction.playSoundFileNamed("torpedo.mp3", waitForCompletion: false))

var touch:UITouch = touches.anyObject() as! UITouch 
var location:CGPoint = touch.locationInNode(self)

var torpedo:SKSpriteNode = SKSpriteNode(imageNamed: "torpedo")
torpedo.position = player.position

torpedo.physicsBody = SKPhysicsBody(circleOfRadius: torpedo.size.width/2)
torpedo.physicsBody!.dynamic = true
torpedo.physicsBody!.categoryBitMask = photonTorpedoCategory
torpedo.physicsBody!.contactTestBitMask = alienCategory
torpedo.physicsBody!.collisionBitMask = 0
torpedo.physicsBody!.usesPreciseCollisionDetection = true

var offset:CGPoint = vecSub(location, b: torpedo.position)

if (offset.y < 0){
    return

self.addChild(torpedo)

var direction:CGPoint = vecNormalize(offset)

var shotLength:CGPoint = vecMult(direction, b: 1000)

var finalDestination:CGPoint = vecAdd(shotLength, b: torpedo.position)

let velocity = 568/1
let moveDuration:Float = Float(self.size.width) / Float(velocity)

var actionArray:NSMutableArray =  NSMutableArray()
actionArray.addObject(SKAction.moveTo(finalDestination, duration: NSTimeInterval(moveDuration)))
actionArray.addObject(SKAction.removeFromParent())

torpedo.runAction(SKAction.sequence(actionArray)) //<-- Here is Error

}

有人可以帮助我吗?