function getKeyValues($arr, $key)
{
    $ret = [];
 
    foreach ($arr as $row) {
        if (is_array($row) && array_key_exists($key, $row)) {
            $ret[] = $row[$key];
        } elseif ($row instanceof \ArrayObject) {
            $row->offsetExists($key) && $ret[] = $row->offsetGet($key);
        }
    }
 
    return $ret;
}