code: func (s *Specifier) Normalize() error {
  	if s.TemplateName == "" {
  		return errors.New("empty template_name")
  	}
  	for k, v := range s.Params {
  		if k == "" {
  			return errors.New("empty param key")
  		}
  		if err := v.Normalize(); err != nil {
  			return fmt.Errorf("param %q: %s", k, err)
  		}
  	}
  	return nil
  }
docs: // Normalize will normalize this Specifier