Ios 无法转换类型为'；AES'；到预期的参数类型'；不安全指针&x27；

我对此代码有一些问题：

import UIKit
import Foundation
import CryptoSwift
class StartViewController: UIViewController {
override func viewDidLoad() {
        super.viewDidLoad()
let key = "bbC2H19lkVbQDfakxcrtCCQdd0FloLyw" 
        let iv = "gqLOHUioQ0QjhusP" 
        let s = "my test string"
do {
            let data = s.data(using: .utf8)
            let enc = try AES(key:key,iv:iv,blockMode:.CBC,padding:PKCS7())
            let encData = NSData(bytes:enc,length:Int(enc.count))

        } catch {
            print("error")
        }
}  

现在让我看看这个错误：

Cannot convert value of type 'AES' to expected argument type 'UnsafeRawPointer?'