     
     private class func update(value: String, forKey key: String) -> Bool {
         
-        var searchDictionary = newSearchDictionary(forKey: key)
+        let searchDictionary = newSearchDictionary(forKey: key)
         var updateDictionary = [String: AnyObject]()
         
         updateDictionary[kSecValueData as String] = value.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)

    
    private class func basicDictionary() -> [String: AnyObject] {
        
        let serviceName = NSBundle(forClass: self).infoDictionary![kCFBundleIdentifierKey] as! String
        
        return [kSecClass as String : kSecClassGenericPassword, kSecAttrService as String : serviceName]
    }

    }
    
    private class func deleteValue(forKey key: String) -> Bool {
        let searchDictionary = newSearchDictionary(forKey: key)
        let status = SecItemDelete(searchDictionary)
        
        return status == errSecSuccess
