Error "cannot convert data (type interface{}) to type string: need type assertion" in Go

Hello everyone! I just started learning Go and encountered an unclear error. I'm writing a simple program that receives data from JSON and tries to use it. Here is my code: ```go package main import ( "encoding/json" "fmt" ) func main() { jsonString := `{"name": "John", "age": 30}` var data interface{} json.Unmarshal([]byte(jsonString), &data) name := data["name"] // Error: cannot convert data (type interface {}) to type string: need type assertion fmt.Println(name) } ``` I expected that `data["name"]` would return the string "John", but the compiler gives an error: "cannot convert data (type interface {}) to type string: need type assertion". I understand that `data` is of type `interface{}`, but how do I get the string value? I tried writing `data.(ma