code: function (path) {
      const foldername = parentPath(path);
  
      return this._getFileId(foldername).then((parentId) => {
        if (parentId) {
          return Promise.resolve(parentId);
        } else {
          return this._createFolder(foldername);
        }
      });
    }
docs: Get the ID of a parent path.
  
  Creates the directory if it doesn't exist yet.
  
  @param {string} path - Full path of a directory or file
  @returns {Promise} Resolves with ID of the parent directory.
  
  @private