Wordpress: Delete attachments after a custom post type is deleted.

gistfile1.php

function handle_delete_listing( $post_id )
{
    $cargs = array(
        'post_type' => 'attachment',
        'post_parent' => $post_id
    );

    $attachments = get_children($cargs);

    if ($attachments) {
        foreach ($attachments as $attachment) {
            wp_delete_attachment( $attachment->ID, true );
        }
    }
}

add_action( 'before_delete_post', 'handle_delete_listing' );