             
             // create notification
             
-            var identifier = identifier + String(i + 1)
+            let identifier = identifier + String(i + 1)
             
             let notification = DLNotification(identifier: identifier, alertTitle: alertTitle, alertBody: alertBody, date: nextDate, repeats: .None)
             

            
            content.sound = (notification.soundName == nil) ? UNNotificationSound.default() : UNNotificationSound.init(named: notification.soundName!)
            
            notification.localNotificationRequest = UNNotificationRequest(identifier: notification.identifier!, content: content, trigger: trigger)
            
            let center = UNUserNotificationCenter.current()

        // Create multiple Notifications
        
        self.scheduleNotification(notification: notification)
        let intervalDifference = Int( toDate.timeIntervalSince(fromDate) / interval )
        
        var nextDate = fromDate
        
