swift – 来自'[NSObject：AnyObject]？’不相关的类型’NSDictionary’总是失败

这行让userInfo = notification.userInfo为！ NSDictionary我得到一个警告：来自'[NSObject：AnyObject]？’不相关的类型’NSDictionary’总是失败

我尝试使用let userInfo = notification.userInfo作为！字典< NSObject：AnyObject>将let userInfo = notification.userInfo替换为！的NSDictionary.但我收到一个错误：预计’>’完成通用参数列表.如何修复警告.

Xcode 7.1 OS X Yosemite

这是我的代码：

func keyboardWillShow(notification: Nsnotification) {

    let userInfo = notification.userInfo as! NSDictionary //warning

    let keyboardBounds = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSvalue).CGRectValue()
    let duration = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as! NSnumber).doubleValue
    let keyboardBoundsRect = self.view.convertRect(keyboardBounds,toView: nil)

    let keyboardInputViewFrame = self.finishView!.frame

    let deltaY = keyboardBoundsRect.size.height

    let animations: (()->Void) = {

        self.finishView?.transform = CGAffineTransformMakeTranslation(0,-deltaY)
    }

    if Duration > 0 {



    } else {

        animations()
    }


}

func keyboardWillShow(notification: Nsnotification) {
    if let userInfo = notification.userInfo {
        ...
    }
}