code: func (r *Render) Add(name string, tmpl *template.Template) {
  	if tmpl == nil {
  		panic("template can not be nil")
  	}
  	if len(name) == 0 {
  		panic("template name cannot be empty")
  	}
  	r.Templates[name] = tmpl
  }
docs: // Add assigns the name to the template