code: def _save_params(self):
          
          self.model.save_params_to_file(self.current_params_fname)
          utils.cleanup_params_files(self.model.output_dir, self.max_params_files_to_keep, self.state.checkpoint,
                                     self.state.best_checkpoint, self.keep_initializations)
docs: Saves model parameters at current checkpoint and optionally cleans up older parameter files to save disk space.