public function getExceptionByIdentifier($identifier)
    {
        $key = strtolower($identifier);

        if (!isset($this->exceptions[$key])) {
            return;
        }

        list($identifier, $name) = $this->exceptions[$key];

        return array(
            $name,
            'https://spdx.org/licenses/' . $identifier . '.html#licenseExceptionText',
        );
    }