You can make it by one line:
mymap := map[string]interface{}{"foo": map[string]interface{}{"first": 1}, "boo": map[string]interface{}{"second": 2}}
for k, v := range mymap {
fmt.Println("k:", k, "v:", v)
}
Output is:
k: foo v: map[first:1]
k: boo v: map[second:2]