创建一个通用的Swift函数来返回一个Core Data实体数组

我的代码中有几个函数返回特定实体类型的数组：

func fetchStores() -> [Store]? {
  var stores: [Store]?
  let fetchRequest: NSFetchRequest<Store> = Store.fetchRequest()

  do {
    stores = try ad.persistentContainer.viewContext.fetch(fetchRequest)
  } catch {
    assert(false,error.localizedDescription)
  }

  return stores
}

我想创建一个处理所有实体的泛型函数：

func fetchEntities<T: NSManagedObject>(entity: T) -> [T]? {
  var results: [T]?

  if let fetchRequest: NSFetchRequest<T> = T.fetchRequest() as? NSFetchRequest<T> {
    do {
      results = try ad.persistentContainer.viewContext.fetch(fetchRequest)
    } catch  {
      assert(false,error.localizedDescription)
    }
  } else {
    assert(false,"Error: cast to NSFetchRequest<T> failed")
  }

  return results
}

// Usage:
let store = Store()
let stores = fetchEntities(entity: store)

有没有办法让我这样做而无需创建Store实例？

TIA