How to get front camera, back camera and audio with AVCaptureDeviceDiscoverySession

Before iOS 10 came out I was using the following code to get the video and audio capture for my video recorder:

 for device in AVCaptureDevice.devices()
 {
     if (device as AnyObject).hasMediaType( AVMediaTypeAudio )
     {
         self.audioCapture = device as? AVCaptureDevice
     }
     else if (device as AnyObject).hasMediaType( AVMediaTypeVideo )
     {
         if (device as AnyObject).position == AVCaptureDevicePosition.back
         {
             self.backCameraVideoCapture = device as? AVCaptureDevice
         }
         else
         {
             self.frontCameraVideoCapture = device as? AVCaptureDevice
         }
     }
 }

When iOS 10 finally came out, I received the following warning when I was running my code. Note that my video recorder was still working smoothly for about 2 weeks.

'devices()' was deprecated in iOS 10.0: Use AVCaptureDeviceDiscoverySession instead.

As I was running my code this morning, my video recorder stopped working. xCode8 does not give me any errors but the previewLayer for the camera capture is completely white. When I then start recording I receive the following error:

Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSLocalizedDescription=The operation could not be completed, NSUnderlyingError=0x17554440 {Error Domain=NSOSStatusErrorDomain Code=-12780 "(null)"}, NSLocalizedFailureReason=An unknown error occurred (-12780)}

I believe that has something to do with the fact that I am using the deprecated approach AVCaptureDevice.devices(). Hence, I was wondering how to use AVCaptureDeviceDiscoverySession instead?

Thank you for your help in advance!

You can get the front camera with the following:

AVCaptureDevice.default(.builtInWideAngleCamera, for: AVMediaType.video, position: .front)

The back camera:

AVCaptureDevice.default(.builtInWideAngleCamera, for: AVMediaType.video, position: .back)

And the microphone:

AVCaptureDevice.default(.builtInMicrophone, for: AVMediaType.audio, position: .unspecified)