数据类型判断问题

```go for k, v := range gobook2 { switch v2 := v.(type) { case string: fmt.Println(k, "is string", v2) case int: fmt.Println(k, "is int", v2) case bool: fmt.Println(k, "is bool", v2) /*case []interface{}: fmt.Println(k, "is an arry: ") for i, iv := range v2 { fmt.Println(i, iv) }*/ default: fmt.Println(k, "is another type not handle yet") } } ``` 这是结果: IsPublished is bool true Price is another type not handle yet Title is string Golang programming Authors is another type not handle yet Publisher is string ituring.com.cn 我想问:v2到底是个什么东西?