How to check if iPhone has dual camera?

Just as the apple's example:

if let device = AVCaptureDevice.defaultDevice(withDeviceType: .builtInDuoCamera,
                                                  mediaType: AVMediaTypeVideo,
                                                  position: .back) {
        return device
    } else if let device = AVCaptureDevice.defaultDevice(withDeviceType: .builtInWideAngleCamera,
                                                  mediaType: AVMediaTypeVideo,
                                                  position: .back) {
        return device
    } else {
        return nil
    }