[Swift]コンバートエラー対応

古いバージョンのSwiftサンプルコードを持ってきて動かそうとしたときに、エラーとなったのとその対応方法

"options: nil"の記述がダメっぽい。

Nil is not compatible with expected argument type 'NSLayoutFormatOptions'
            preferredView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[imageView]|",
                options: nil, metrics: nil, views: ["imageView": imageView]))
            preferredView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[imageView]|",
                options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["imageView": imageView]))

• error Nil default argument value of cannot be converted to type ‘NSLayoutFormatOptions’

error Nil default argument value of cannot be converted to type 'NSLayoutFormatOptions'

I have upgraded to swift 2 and this function has created a headache for me.This is causing the error when trying to run ...

stackoverflow.com

func addConstraints(format format: String, options: NSLayoutFormatOptions? = nil, metrics: [String: AnyObject]? = nil, views: [String: UIView])
func addConstraints(format format: String, options: NSLayoutFormatOptions, metrics: [String: AnyObject]? = nil, views: [String: UIView])