code: public void writeSBGN(Model model, OutputStream stream) {
  		Sbgn sbgn = createSBGN(model);
  		try {
  			JAXBContext context = JAXBContext.newInstance("org.sbgn.bindings");
  			Marshaller marshaller = context.createMarshaller();
  			marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
  			marshaller.marshal(sbgn, stream);
  		} catch (JAXBException e) {
  			throw new RuntimeException("writeSBGN: JAXB marshalling failed", e);
  		}
  	}
docs: Converts the given model to SBGN, and writes in the specified output stream.
  
  @param model model to convert
  @param stream output stream to write