/**
* @return int|null
*/
public function getIndex()
{
if ($this->parent === null) {
return null;
}
return $this->parent->getChildIndex($this);
}
/**
* @return int|null
*/
public function getIndex()
{
if ($this->parent === null) {
return null;
}
return $this->parent->getChildIndex($this);
}