code: public void writeToStreamWithoutFactors(OutputStream outputStream) throws IOException {
          Set<GraphicalModel.Factor> emptySet = new HashSet<>();
          for (GraphicalModel model : this) {
              Set<GraphicalModel.Factor> cachedFactors = model.factors;
              model.factors = emptySet;
              model.writeToStream(outputStream);
              model.factors = cachedFactors;
          }
      }
docs: This writes the whole batch, WITHOUT FACTORS, which means that anyone loading this batch will need to include
  their own featurizer. Make sure that you have sufficient metadata to be able to do full featurizations.
  
  @param outputStream the outputstream to write our files to
  @throws IOException