code: function (selector) {
              var ret, self = this;
              if (self.length > 0) {
                  ret = Node.all(selector, self);
              } else {
                  ret = new Node();
              }
              ret.__parent = self;
              return ret;
          }
docs: Get node list which are descendants of current node list.
  @param {String} selector Selector string
  @return {KISSY.Node}