show chunk if parent is:

gistfile1.txt

$current_docid = $modx->resource->get('parent');
$output ='';

if($current_docid ==8){
    $output = $modx->getChunk('this_chunk');
}

elseif($current_docid ==9){
    $output = $modx->getChunk('this_chunk');
}

return $output;