code: function (id) {
      return this._request('GET', BASE_URL + '/drive/v2/files/' + id, {}).then(function (response) {
        if (response.status === 200) {
          return Promise.resolve(JSON.parse(response.responseText));
        } else {
          return Promise.reject("request (getting metadata for " + id + ") failed with status: " + response.status);
        }
      });
    }
docs: Get the metadata for a given file ID.
  
  @param {string} id - File ID
  @returns {Promise} Resolves with an object containing the metadata
  
  @private