App Crashes when trying to fetch data from core data

I am trying to save two types of arrays using Core Data. One array contains UIimages, and the other Array contains URL's of videos. I am able to successfully save them using this method below.

 let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext
    let newVideo = NSEntityDescription.insertNewObject(forEntityName: "Content", into: context)
    videosArray.append(session.outputURL!)
    let thumbnail = self.getThumbnail(session.outputURL!)
    thumbnails.append(thumbnail)
    newVideo.setValue(videosArray, forKey: "videos")
    newVideo.setValue(thumbnails, forKey: "thumbnails")

    do {

        try context.save()
        print("Save")

    } catch {
        print("Error")
        // Process error
    }

I get the Save message printed out. However while trying to load them in the collection view i get a crash.

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Content")
    request.returnsObjectsAsFaults = false

    do {
        let results = try context.fetch(request)
        if results.count > 0 {
            for result in results as! [NSManagedObject] {
                if let fetchedThumbnails = (result).value(forKey: "thumbnails") as? Array<Any> {
                    return fetchedThumbnails.count
                }
            }
        }
    } catch {
        print("There was a crash fetching content")
    }

    return 0
}

The collection view is supposed to return as many thumbnails that are in the array. However it crashes and takes me to the app delegate file.

I set a breakpoint at

let results = try context.fetch(request)

And it goes to the breakpoint.

Then i set another breakpoint at

if results.count > 0 {

and the app crashes and takes me to the app delegate with this error:

Terminating app due to uncaught exception 
'NSInvalidArgumentException', 
reason: '-[Content initWithCoder:]: 
unrecognized selector sent to instance 0x174a6d840'

Image of how I Declare Entity