/**
 * Inserts the current node as last child of given $parent node
 * The modifications in the current object and the tree
 * are not persisted until the current object is saved.
 *
 * @param   $parent Propel object for parent node
 * @return $this| The current Propel object
 */
public function insertAsLastChildOf( $parent)
{
    if ($this->isInTree()) {
        throw new PropelException(
            'A  object must not already be in the tree to be inserted. Use the moveToLastChildOf() instead.'
        );
    }

    $left = $parent->getRightValue();
    // Update node properties
    $this->setLeftValue($left);
    $this->setRightValue($left + 1);
    $this->setLevel($parent->getLevel() + 1);

    // update the children collection of the parent
    $parent->addNestedSetChild($this);

    // Keep the tree modification query for the save() transaction
    $this->nestedSetQueries []= array(
        'callable'  => array('', 'makeRoomForLeaf'),
        'arguments' => array($left, $this->isNew() ? null : $this)
    );

    return $this;
}