map type conversion

[jicui]

Here is my code example below
func TestJson(t *testing.T){
sjson,:=simplejson.NewJson([]byte(foo()))
v,:=sjson.Get("listmap").Get("100").String()
fmt.Println(v)//Barcode_PreDelivery_STH-Electronic_Instant_Download
}

func TestJsonMap(t *testing.T){
sjson:=simplejson.New()
listmap:=make(map[string]string)
listmap["100"]="Barcode_PreDelivery_STH-Electronic_Instant_Download"
sjson.Set("listmap",listmap)
v,er:=sjson.Get("listmap").Get("100").String()
fmt.Print(er)//raise type assertion to string failed
fmt.Println(v)//Barcode_PreDelivery_STH-Electronic_Instant_Download

body, _ := sjson.MarshalJSON()
fmt.Println(string(body))

}

func foo() string {
return "{"listmap":{"100":"Barcode_PreDelivery_STH-Electronic_Instant_Download"}}\n";
}

the fist test "TestJson" success to parse the foo string and get value by Get("listmap").Get("100").String()
the second test "TestJsonMap" fails on fetch by
Get("listmap").Get("100").String() and raise "type assertion to string failed"

anything I'm missing here ,appreciated any help

[jicui]

name = "github.com/bitly/go-simplejson"
version = "0.5.0"