gob: type not registered for interface: []interface {}

I am trying to copy a map to another map so i used gob in order to do this. But when i unmarshal a json to map[string]interface{} and then try to copy it to another map i get an error in the encoding part.

This is the code:

 package main import ( "encoding/gob" "bytes" "fmt" "encoding/json" ) func CopyMapToAnotherMap(req map[string]interface{}) (cpy map[string]interface{}, err error) { var mod bytes.Buffer gob.Register(map[string]interface{}{}) enc := gob.NewEncoder(&mod) dec := gob.NewDecoder(&mod) err = enc.Encode(req) if err != nil { fmt.Println("Unable to encode map", err) return nil, err } err = dec.Decode(&cpy) if err != nil { fmt.Println("Unable to decode map", err) return nil, err } return cpy, nil } func main() { my := `{"data":[{"aa":1},{"bb":2}]}` var m map[string]interface{} err := json.Unmarshal([]byte(my), &m) if err != nil { fmt.Println(err) } CopyMapToAnotherMap(m) } 

and i am getting an error : gob: type not registered for interface: []interface {}

How can this be avoided?