private function convertToTimestamp($str)
    {
        $result = date_parse($str);
        if (!$result) {
            return false;
        }
        if (empty($result) || !is_array($result)) {
            return false;
        }
        extract($result);
        if (!empty($errors)) {
            throw new SdkException("SDK failed to parse date value \"$str\":"
                . (is_array($errors) ? implode("\n", $errors) : $errors)
            );
        }

        //@TODO: mktime is deprecated since 5.3.0, this package needs 5.6
        return mktime($hour, $minute, $second, $month, $day, $year);
    }