Swift NSUserDefaults unexpectedly found nil while unwrapping an Optional value
<p>//Help Please This Code won't work, getting this as feedback from Xcode. 
fatal error: unexpectedly found nil while unwrapping an Optional value</p>

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<pre><code>    var savedScore = NSUserDefaults.standardUserDefaults().objectForKey("HighestScore") as! Int
</code></pre>

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<pre><code>import SpriteKit

class GameScene: SKScene {

    var highestScore:Int = 2
    var score = Int()

    override func didMoveToView(view: SKView) {
        /* Setup your scene here */

        //To save highest score

        //To get the saved score
        var savedScore = NSUserDefaults.standardUserDefaults().objectForKey("HighestScore") as! Int

        print(savedScore)


    }

    override func touchesBegan(touches: Set&lt;UITouch&gt;, withEvent event: UIEvent?) {
       /* Called when a touch begins */
        score += 1
        print("Score - \(score)")

        if score &gt; highestScore
        {
            highestScore = score
            NSUserDefaults.standardUserDefaults().setObject(highestScore, forKey:"HighestScore")
            NSUserDefaults.standardUserDefaults().synchronize()
            print("Beat")
        }

        else {
            print("Not Beat")
        }

    }

    override func touchesMoved(touches: Set&lt;UITouch&gt;, withEvent event: UIEvent?) {

    }

    override func update(currentTime: CFTimeInterval) {
        /* Called before each frame is rendered */
    }
}
</code></pre>