$post_type_object = get_post_type_object ( $post_type );
} elseif ( $this->is_attachment ) {
$where .= " AND {$wpdb->posts}.post_type = 'attachment'";
$post_type_object = get_post_type_object ( $post_type );
} elseif ( $this->is_attachment ) {
$where .= " AND {$wpdb->posts}.post_type = 'attachment'";