public static function addCondition($condition)
    {
        $ret = ' ';

        if (!empty($condition)) {
            if (is_array($condition)) {
                $ret .= ' AND (( ' . implode(" )\nAND (", $condition) . ' ))';
            } else {
                $ret .= ' AND ( ' . $condition . ' )';
            }
        }

        return $ret;
    }