code: public Dataset<String, String> getDataset(Collection<List<IN>> data) {
      return getDataset(data, null, null);
    }
docs: Build a Dataset from some data. Used for training a classifier.
  
  @param data This variable is a list of lists of CoreLabel.  That is,
  it is a collection of documents, each of which is represented
  as a sequence of CoreLabel objects.
  @return The Dataset which is an efficient encoding of the information
  in a List of Datums