if (!empty($parents) && $parents > 0) {
    if (empty($depth)) {$depth = 10;}
    $pids = array_map('trim', explode(',', $parents));
    $parents = $pids;
    foreach ($pids as $v) {
        if (!is_numeric($v)) {continue;}
                $parents = array_merge($parents, $modx->getChildIds($v, $depth));
        }
}