code: public List<List<IN>> classifyFile(String filename) {
      ObjectBank<List<IN>> documents =
        makeObjectBankFromFile(filename, plainTextReaderAndWriter);
      List<List<IN>> result = new ArrayList<List<IN>>();
  
      for (List<IN> document : documents) {
        // System.err.println(document);
        classify(document);
  
        List<IN> sentence = new ArrayList<IN>();
        for (IN wi : document) {
          sentence.add(wi);
          // System.err.println(wi);
        }
        result.add(sentence);
      }
      return result;
    }
docs: Classify the contents of a file.
  
  @param filename
  Contains the sentence(s) to be classified.
  @return {@link List} of classified List of IN.