code: function (id) {
          var val = this.reference[this._postman_listIndexCaseInsensitive ? String(id).toLowerCase() : id];
  
          if (this._postman_listAllowsMultipleValues && Array.isArray(val)) {
              return val.length ? val[val.length - 1] : undefined;
          }
  
          return val;
      }
docs: Get Item in this list by `ID` reference. If multiple values are allowed, the last value is returned.
  
  @param {String} id
  @returns {PropertyList.Type}