code: private void readFrom(InputStream inputStream, Consumer<GraphicalModel> featurizer) throws IOException {
          GraphicalModel read;
          while ((read = GraphicalModel.readFromStream(inputStream)) != null) {
              featurizer.accept(read);
              add(read);
          }
      }
docs: Load a batch of models from disk, while running the function "featurizer" on each of the models before adding it
  to the batch. This gives the loader a chance to experiment with new featurization techniques.
  
  @param inputStream the input stream to load from
  @param featurizer a function that gets run on every GraphicalModel, and has a chance to edit them (eg by adding
  or changing features)