如何使用NSManagedObjectSubClass从CoreData Base获取所有记录？

@objc(ExampleNSManagedObjectSubClass)
class ExampleNSManagedObjectSubClass: NSManagedObjectSubClass {

    override init(entity: NSEntityDescription!, insertIntoManagedObjectContext context: NSManagedObjectContext!) {
        super.init(entity: entity, insertIntoManagedObjectContext: context)
    }

    override func init() {
        super.init()
        // Set default values for all properties
        self.setValue(NSNumber(bool: false), forKey: "isRegistered")
    }

    override func willAccessValueForKey(_ key: Key) {
        super.willAccessValueForKey(key)
        print("Will access value for key: \(key.debugDescription)")
    }

    override func didAccessValueForKey(_ key: Key) {
        super.didAccessValueForKey(key)
        print("Did access value for key: \(key.debugDescription)")
    }

    override func willChangeValueForKey(_ key: Key, forType type: String!) {
        super.willChangeValueForKey(key, forType: type)
        print("Will change value for key: \(key.debugDescription), type: \(type)")
    }

    override func didChangeValueForKey(_ key: Key, forType type: String!) {
        super.didChangeValueForKey(key, forType: type)
        print("Did change value for key: \(key.debugDescription), type: \(type)")
    }

    func fetchAllObjects() -> [ExampleNSManagedObjectSubClass] {
        return []
    }
}

let moc = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
let exampleObjectSubClass = ExampleNSManagedObjectSubClass(entity: entity, insertIntoManagedObjectContext: moc)
let objects = exampleObjectSubClass.fetchAllObjects()