NSException when trying to save to camera roll

Question

What I am trying to do it to save what's on my 'canvasView' to photos when a UIButton is pressed. However I am getting the following:

ERROR

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[drawingskills.ViewController saveDrawingToCamera:]: unrecognized selector sent to instance 0x7ff67bd04b60'
terminating with uncaught exception of type NSException

The steps I took are as follows:

STEP 1

Create UIBtton and link it to a function called saveDrawingToCameraRoll

STEP 2

set up the function as below:

func saveDrawingToCameraRoll(_ sender: Any) {
            UIGraphicsBeginImageContextWithOptions(canvasView.bounds.size, false, UIScreen.main.scale)
            canvasView.drawHierarchy(in: canvasView.bounds, afterScreenUpdates: true)
            
            let image = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            
            if image != nil {
                PHPhotoLibrary.shared().performChanges({
                    PHAssetChangeRequest.creationRequestForAsset(from: image!)
                })   
            }   
    }

STEP 3

Info.plist -> right click -> add row ->select "privacy - photo library usage description" from drop down

However this all results in the error mentioned at the start of this text.