Golang 嵌套map赋值办法

http://my.oschina.net/sol/blog/159060

m := map[string]map[string]string{}
mm, ok := m["kkk"]
if !ok {
    mm = make(map[string]string)
    m["kkk"] = mm
}
mm[k1k1k1] = "sssss"