interface ClockInterface {
    tick()
}

interface ClockConstructor {
    new(h:number,m:number):ClockInterface
}

function createClock(ctor:ClockConstructor,hour:number,minute:number) : ClockInterface {
    return new ctor(hour,minute)
}

class DigitalClock implements ClockInterface{
    
    constructor(h:number,m:number) {

    }
    tick() {
        console.log('beep beep')
    }

}

class AnalogClock implements ClockInterface {
    constructor(h:number,m:number) {

    }
    tick() {
        console.log('tick tock')
    }
}

let digit = createClock(DigitalClock,12,17)

let analog = createClock(AnalogClock,7,32)

老师这个createClock第一个参数不是构造器接口么，为什么传入的是继承ClockInterface 的类，类型不会不一致么