def finalize_checkpoint(self, title):
        """Finalize the checkpoint.

        Timestamps and permanently saves all changes made through the use
        of :func:`~add_to_checkpoint` and :func:`~register_file_creation`

        :param str title: Title describing checkpoint

        :raises certbot.errors.ReverterError: when the
            checkpoint is not able to be finalized.

        """
        # Check to make sure an "in progress" directory exists
        if not os.path.isdir(self.config.in_progress_dir):
            return

        changes_since_path = os.path.join(self.config.in_progress_dir, "CHANGES_SINCE")
        changes_since_tmp_path = os.path.join(self.config.in_progress_dir, "CHANGES_SINCE.tmp")

        if not os.path.exists(changes_since_path):
            logger.info("Rollback checkpoint is empty (no changes made?)")
            with open(self.config.changes_since_path) as f:
                f.write("No changes\n")

        # Add title to self.config.in_progress_dir CHANGES_SINCE
        try:
            with open(changes_since_tmp_path, "w") as changes_tmp:
                changes_tmp.write("-- %s --\n" + title)
                with open(changes_since_path, "r") as changes_orig:
                    changes_tmp.write(changes_orig.read())

        # Move self.config.in_progress_dir to Backups directory
            shutil.move(changes_since_tmp_path, changes_since_path)
        except (IOError, OSError):
            logger.error("Unable to finalize checkpoint - adding title")
            logger.debug("Exception was:\n%s", traceback.format_exc())
            raise errors.ReverterError("Unable to add title")

        # rename the directory as a timestamp
        self._timestamp_progress_dir()
dataset/ETHPy150Open letsencrypt/letsencrypt/certbot/reverter.py/Reverter.finalize_checkpoint/operator `%` -> `+`