docs: function (file, ext) {
          var fileHandler = _.find(this.handlers, function (handler) {
              return _.includes(handler.extensions, ext);
          });
  
          return fileHandler.loadFile([_.pick(file, 'name', 'path')]).then(function (loadedData) {
              // normalize the returned data
              var importData = {};
              importData[fileHandler.type] = loadedData;
              return importData;
          });
      }