     fileprivate let identifier: String
     fileprivate let bundle: Bundle
     private let directory: FileManager.SearchPathDirectory
+    private let groupIdentifier: String?
     fileprivate let mergePolicy: NSMergePolicyType
     fileprivate let wipeOnConflict: Bool
     fileprivate let sharedBackgroundContext: Bool

        fatalError()
    }
    
    init(modelName: String, type: String = NSSQLiteStoreType, identifier: String, bundle: Bundle, in directory: FileManager.SearchPathDirectory = .documentDirectory, mergePolicy: NSMergePolicyType = .mergeByPropertyObjectTrumpMergePolicyType, wipeOnConflict: Bool, sharedBackgroundContext: Bool) {
        
        self.modelName = modelName
        self.type = type
        self.identifier = identifier
        self.bundle = bundle
        self.directory = directory
        self.mergePolicy = mergePolicy
        self.wipeOnConflict = wipeOnConflict
        self.sharedBackgroundContext = sharedBackgroundContext

        }
    }
    
    public convenience init(modelName: String, identifier: String = Bundle.main.bundleIdentifier!, bundle: Bundle = Bundle.main, groupIdentifier: String, wipeOnConflict: Bool = false) {
        self.init(modelName: modelName, storeType: NSSQLiteStoreType, identifier: identifier, bundle: bundle, in: .documentDirectory, groupIdentifier: groupIdentifier, wipeOnConflict: wipeOnConflict)
    }

    public init(modelName: String, storeType: String = NSSQLiteStoreType, identifier: String = Bundle.main.bundleIdentifier!, bundle: Bundle = Bundle.main, in directory: FileManager.SearchPathDirectory = .documentDirectory, groupIdentifier: String? = nil, wipeOnConflict: Bool = false, sharedBackgroundContext: Bool = false) {
        stack = LegacyDataStack(modelName: modelName, type: storeType, identifier: identifier, bundle: bundle, in: directory, groupIdentifier: groupIdentifier, wipeOnConflict: wipeOnConflict, sharedBackgroundContext: sharedBackgroundContext)

        /*if #available(iOS 10, tvOS 10, *) {
            stack = CoreDataStack(modelName: modelName, type: storeType, identifier: identifier, in: directory, wipeOnConflict: wipeOnConflict)
