Xcode 8（swift 3）它的实体类型是什么？

Question

实体的正确类型是什么？

例如，在将值保存到实体的属性时，哪种类型声明应该替换下面的三个问号？

func setSample() {
    let saveSample: <type???> = SampleEntity(context: context)
    saveSample.sampleAttribute = "Save a new string."
    do {
        try context.save()
    } catch {
         print("Error with save: \(error)")
    }
}

FWIW：NSEntityDescription返回错误：

Cannot convert value of type 'SampleEntity' to specified type 'NSEntityDescription'
Value of type 'NSEntityDescription' has no member 'sampleAttribute'

上下文我想把实体变成一个变量来做这样的事情：

func setSample() {
    var saveSample: ??? 
    if (criteria) { saveSample = Entity1(context: context) }
    if (criteria) { saveSample = Entity2(context: context) }
    if (criteria) { saveSample = Entity3(context: context) }
    saveSample.sampleAttribute1 = "Foo"
    saveSample.sampleAttribute2 = "Bar"
    saveSample.sampleAttributeNth = "Etc"
    do {
        try context.save()
    } catch {
         print("Error with save: \(error)")
    }
}

Answer 1

使用??? = SampleEntity或完全删除???部分：

let saveSample = SampleEntity(context: context)
let saveSample: SampleEntity = SampleEntity(context: context)
let saveSample: SampleEntity