regularlabs/src/ArrayHelper.php:414

Hello,
Our site was working fine until today.
We have the following syntax error, which has taken down our site. How do we resolve this error:
0 syntax error, unexpected '=>' (T_DOUBLE_ARROW), expecting ')'
/home/ynztvmmx/public_html/libraries/regularlabs/src/ArrayHelper.php:414


LINES 399-417::

/**
* Sorts the array by keys based on the values of another array
*
* @param array $array
* @param array $order
*
* @return array
*/
public static function sortByOtherArray($array, $order)
{
if (empty($order))
{
return $array;
}

uksort($array, fn($key1, $key2) => array_search($key1, $order) > array_search($key2, $order));

return $array;
}