code: func (ns *Namespace) Ref(in interface{}, args interface{}) (template.HTML, error) {
  	p, ok := in.(urls.RefLinker)
  	if !ok {
  		return "", errors.New("invalid Page received in Ref")
  	}
  	argsm, err := ns.refArgsToMap(args)
  	if err != nil {
  		return "", err
  	}
  	s, err := p.Ref(argsm)
  	return template.HTML(s), err
  }
docs: // Ref returns the absolute URL path to a given content item.