code: function () {
          var that = this,
              parentInstance = that.getParentInstance(),
              parentValue = parentInstance && parentInstance.extendedCurrentValue(),
              currentValue = $.trim(that.el.val());
  
          return utils.compact([parentValue, currentValue]).join(' ');
      }
docs: Querying related methods 
  Looks up parent instances
  @returns {String} current value prepended by parents' values