Templates in Go

func init() {

    funcMap = template.FuncMap{
        "img": func(imgs []*templateAttachment, name string) (string, error) {
            for i := range imgs {
                if imgs[i].Name == name {
                    return imgs[i].Path, nil
                }
            }
            return "", &AppError{
                Action: "FuncMap",
                Unit:   "Template",
                Text:   fmt.Sprintf("Image attachment %v is not found", name),
            }
        },
    }
}

func ParseTemplate(.....){
   ......
   templateParser, err := template.New("Email").Funcs(funcMap).Parse(content)
    if err != nil {
        return "", err
    }
    wr := bytes.NewBufferString("")
    err = templateParser.Execute(wr, tplVars)
    if err != nil {
        return "", err
    }
}