code: func (extr *ContentExtractor) GetMetaContents(document *goquery.Document, metaNames *set.Set) map[string]string {
  	contents := make(map[string]string)
  	counter := metaNames.Size()
  	document.Find("meta").EachWithBreak(func(i int, s *goquery.Selection) bool {
  		attr, exists := s.Attr("name")
  		if exists && metaNames.Has(attr) {
  			content, _ := s.Attr("content")
  			contents[attr] = content
  			counter--
  			if counter < 0 {
  				return false
  			}
  		}
  		return true
  	})
  	return contents
  }
docs: // GetMetaContents returns all the meta tags as name->content pairs