public function query($statement)
    {
        if (1 == func_num_args()) {
            return $this->getPDO()->query($statement);
        }
        // this way is much slower but supports overloading
        // http://php.net/manual/en/pdo.query.php
        return call_user_func_array(array($this->getPDO(), __FUNCTION__), func_get_args());
    }