Inpsyde\MultilingualPress\API\WPDBSiteRelations::get_value_pair PHP Method

    private function get_value_pair($site_1, $site_2)
    {
        $site_1 = (int) $site_1;
        $site_2 = (int) $site_2;
        // Swap values to make sure the lower value is the first.
        if ($site_1 > $site_2) {
            list($site_1, $site_2) = [$site_2, $site_1];
        }
        return "({$site_1}, {$site_2})";
    }