code: function (key) {
              var keys = Array.isArray(key) ? key : arguments;
  
              var input = self.input.all();
              var results = {};
  
              for (var i = 0; i < keys.length; i++) {
                  results[keys[i]] = input[keys[i]];
              }
  
              return results;
          }
docs: Get a subset of the items from the input data.
  
  @param  {Array|String}  key
  @return {Array}