code: def get_storage(key, username):
      
      if IS_APPENGINE and appengine:
          return appengine.StorageByKeyName(
              appengine.CredentialsModel, username, 'credentials')
      file_name = os.path.expanduser('~/.config/webreview/{}_{}'.format(key, username))
      dir_name = os.path.dirname(file_name)
      if not os.path.exists(dir_name):
          os.makedirs(dir_name)
      return oauth_file.Storage(file_name)
docs: Returns the Storage class compatible with the current environment.