is it possible counting number of children given tree in flex ?

Question

myTree is

updateParents(XML(myTree.selectedItem))

private function  updateParents(item:XML):void
    {
item.children().length();

Count.text=item.toString();

}

In my application I used treeview with checkbox . How can I calculate (childnode node only) checkbox selected count in treeview . please refer any url for count the child node in tree

http://www.sephiroth.it/weblog/archives/2006/09/flex2%5Fagain%5Fcheckbox%5F3state.php