public function setFetchDepth($fetchDepth = null)
{
if (!$this->useFetchDepth) {
return 0;
}
$oldFetchDepth = $this->session->getSessionOption($this->useFetchDepth);
if (isset($fetchDepth)) {
$this->session->setSessionOption($this->useFetchDepth, $fetchDepth);
}
return $oldFetchDepth;
}