code: func NewStopwords() StopWords {
  	cachedStopWords := make(map[string]*set.Set)
  	for lang, stopwords := range sw {
  		lines := strings.Split(stopwords, "\n")
  		cachedStopWords[lang] = set.New(set.ThreadSafe).(*set.Set)
  		for _, line := range lines {
  			if strings.HasPrefix(line, "#") {
  				continue
  			}
  			line = strings.TrimSpace(line)
  			cachedStopWords[lang].Add(line)
  		}
  	}
  	return StopWords{
  		cachedStopWords: cachedStopWords,
  	}
  }
docs: // NewStopwords returns an instance of a stop words detector