source code 2.3.0.2

if (isset($this->request->get['filter_instock'])) {
$filter_instock = $this->request->get['filter_instock'];
} else {
$filter_instock = '';
}
$this->data['filter_instock'] = $filter_instock;
if (isset($this->request->get['filter_instock'])) {
$url .= '&filter_instock=' . $this->request->get['filter_instock'];
}


am i correct to write this source code format at 2.3.0.2 ??

It's $data, without $this.