Null result in NewSimpleQueryStringQuery() with Golang

[Mehrdad.dev (Mehrdad Mohammadiyan)]

Hi.
I want search a query string with NewSimpleQueryStringQuery() function.

my code is :

func Search(ctx context.Context, client *elastic.Client, index string) {
	var companies []People
	q := `{
		"query": {
		  "simple_query_string" : {
			"query":    "mahmood rahimi",
			"fields": [ "Firstname", "Lastname" ] 
		  }
		}
	}`
	result := elastic.NewSimpleQueryStringQuery(q)
	searchResult, err := client.Search().
		Index(index).
		// Type("article").
		Query(result).
		Do(ctx)
	if err != nil {
		fmt.Println(err)
	}`

	for _, hit := range searchResult.Hits.Hits {
		var cmp People
		fmt.Println(hit.Source)
		err := json.Unmarshal(hit.Source, &cmp)
		if err != nil {
			fmt.Println(err)
		}
		fmt.Println(cmp)
		companies = append(companies, cmp)
	}
	fmt.Println(companies)
}

But the result printing companies in null.

Can you help me ?