code: func (p *Tagger) Lemmatize(a string, pt lingo.POSTag) ([]string, error) {
  	if p.Lemmatizer == nil {
  		return nil, componentUnavailable("lemmatizer")
  	}
  	return p.Lemmatizer.Lemmatize(a, pt)
  }
docs: // Lemmatize implements the lingo.Lemmatize interface. It however, defers the actual doing of the job to the Lemmatizer.