code: func (p *pageMeta) RelatedKeywords(cfg related.IndexConfig) ([]related.Keyword, error) {
  
  	v, err := p.Param(cfg.Name)
  	if err != nil {
  		return nil, err
  	}
  
  	return cfg.ToKeywords(v)
  }
docs: // RelatedKeywords implements the related.Document interface needed for fast page searches.