code: func (t *Template) Apply(s string) (string, error) {
  	var out bytes.Buffer
  	tmpl, err := template.New("tmpl").
  		Option("missingkey=error").
  		Funcs(template.FuncMap{
  			"time": func(s string) string {
  				return time.Now().UTC().Format(s)
  			},
  		}).
  		Parse(s)
  	if err != nil {
  		return "", err
  	}
  
  	err = tmpl.Execute(&out, t.fields)
  	return out.String(), err
  }
docs: // Apply applies the given string against the fields stored in the template.