code: def save_model(self, file_name='model.sbgn'):
          
          model = self.print_model()
          with open(file_name, 'wb') as fh:
              fh.write(model)
docs: Save the assembled SBGN model in a file.
  
          Parameters
          ----------
          file_name : Optional[str]
              The name of the file to save the SBGN network to.
              Default: model.sbgn