code: func RegisterTemplateLoader(key string, loader func(loader *TemplateLoader) (TemplateEngine, error)) (err error) {
  	if _, found := templateLoaderMap[key]; found {
  		err = fmt.Errorf("Template loader %s already exists", key)
  	}
  	templateLog.Debug("Registered template engine loaded", "name", key)
  	templateLoaderMap[key] = loader
  	return
  }
docs: // Allow for templates to be registered during init but not initialized until application has been started