code: public String predict(LabelledDocument document) {
          if (document.getReferencedContent() != null)
              return predict(document.getReferencedContent());
          else
              return predict(document.getContent());
      }
docs: This method predicts label of the document.
  Computes a similarity wrt the mean of the
  representation of words in the document
  @param document the document
  @return the word distances for each label