"//node[label = '$bldg']/node[label = '$floor']/label/text()"

##</code><code>##

"//node[label = '$bldg']/node[label = '$floor']/label"

##</code><code>##

$newnode = $parent->addSibling($new_element);

##</code><code>##

$node->addSibling($new_element);