text: const backupKey = 'backup';
  
  export default class BackupManager {
    #storageManager;
  
    constructor(storageManager) {
      this.#storageManager = storageManager;
    }
    getBackup() {
      return this.#storageManager.get(backupKey);
    }
    setBackup(data) {
      this.#storageManager.set(backupKey, data);
    }
    clearBackup() {
      this.#storageManager.delete(backupKey);
    }
  }