code: function child(part) {
          var element = this;
          if (part.charAt(0) in IE) {// if nested emmet action, recurse on
              return _.emmet(element, part);
          }
          if (this instanceof X.List) {
              return this.insert(part);
          }
          element = D.createElement(part);
          this.appendChild(element);
          return element;
      }
docs: add node(s)