WidgetKit Core Data

Code Block 
2020-06-23 19:15:50.041978-0400 AssignmentsExtension[94980:3425649] [error] error: +[Assignments entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass
CoreData: error: +[Assignments entity] Failed to find a unique match for an NSEntityDescription to a managed object subclass
Program ended with exit code: 9

Code Block 
 struct LeaderboardEntry: TimelineEntry {
    public let date: Date
    public let assign: String?
}
 struct Provider: TimelineProvider {
    @FetchRequest(entity: Assignments.entity(), sortDescriptors: []) var contactsreq: FetchedResults<Assignments>
    @State var s: String?
   
    public func snapshot(with context: Context,completion: @escaping (LeaderboardEntry) -> ()) {
        let entry = LeaderboardEntry(date: Date(), assign: contactsreq[0].name!)
        s = contactsreq[1].name
        completion(entry)
    }
    public func timeline(with context: Context,
                            completion: @escaping (Timeline<Entry>) -> ()) {
        let entry = LeaderboardEntry(date: Date(), assign: contactsreq[1].name))
           let timeline = Timeline(entries: [entry, entry], policy: .atEnd)
           completion(timeline)
       }
}
struct AssignmentsEntryView : View {
    func dateToSting(d: Date) -> String{
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "EE MMMM d, YYYY"
               
        return dateFormatter.string(from: d)
    }
    
   var entry: LeaderboardEntry
 
    var body: some View {
   
        Text(entry.assign!)
            
        
    
                      
                   }
            
        }
@main
struct AssignmenstWidget: Widget {
    var body: some WidgetConfiguration {
        
        StaticConfiguration(
            kind: "com.mygame.game-status",
            provider: Provider(),
            placeholder: PlaceholderView()
        ) { entry in
            AssignmentsEntryView(entry: entry)
        }
        .configurationDisplayName("Game Status")
        .description("Shows an overview of your game status")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }}