code: function(){
              this._configs = this._configs;
              var keys = [], key;
  
              for (key in this._configs) {
                  if ( Lang.hasOwnProperty(this._configs, key) && 
                          !Lang.isUndefined(this._configs[key]) ) {
                      keys[keys.length] = key;
                  }
              }
              
              return keys;
          }
docs: Returns an array of attribute names.
  @method getAttributeKeys
  @return {Array} An array of attribute names.