golang json map[string]接口的解组部分{}

我有以下代码来尝试解组这个json文件，但是json.Unmarshal([]byte(msg"restaurant")，&restaurant)行总是给出一个错误。如何让Unmarshal忽略"restaurant“或只将"restaurant”数据传递给Unmarshal函数？

谢谢!

{
  "restaurant": {
    "name": "Tickets",
    "owner": {
      "name": "Ferran"
    }
  }
}


    file, e := ioutil.ReadFile("./rest_read.json")
    if e != nil {
            fmt.Println("file error")
            os.Exit(1)
    }

    var data interface{}
    json.Unmarshal(file, &data)

    msg := data.(map[string]interface{})
    log.Println(msg)
    log.Println(msg["restaurant"])
    log.Println(reflect.TypeOf(msg["restaurant"]))

    var restaurant Restaurant
    json.Unmarshal([]byte(msg["restaurant"]), &restaurant)

    log.Println("RName: ", restaurant.Name)
    log.Println("Name: ", restaurant.Owner.Name)