/// <summary>
 /// saving photolibrary to a txt file on disk
 /// </summary>
 public async Task SaveAsync()
 {
     string jsonPhotoLibrary = JsonConvert.SerializeObject(this);
     await FileHelper.WriteTextFileAsync(TEXT_FILE_NAME + Name + ".txt", jsonPhotoLibrary);
 }
 private async Task UpdateFileAsync()
 {
     string jsonPhotoLibrary = JsonConvert.SerializeObject(this.libraryCollection);
     await FileHelper.WriteTextFileAsync(LIBRARY_MANAGER_FILE_NAME, jsonPhotoLibrary);
 }