I added an on_update event to my grid but i am always getting an internal server error. My code is below:

$e[“on_update”] = array(“update_client”, null, true);
$g->set_events($e);

function update_client($data)
{
$myfile = fopen(‘storage/logs/text4.txt’, ‘w’);
$result = print_r($data, true);
fwrite($myfile, $result);
fclose($myfile);
}