SlevomatCodingStandard\Sniffs\Namespaces\FullyQualifiedClassNameAfterKeywordSniff::register PHP Method

    public function register()
    {
        if (count($this->getKeywordsToCheck()) === 0) {
            throw new \SlevomatCodingStandard\Sniffs\Namespaces\NoKeywordsException(self::class, 'keywordsToCheck');
        }
        return array_map(function ($keyword) {
            if (!defined($keyword)) {
                throw new \SlevomatCodingStandard\Sniffs\Namespaces\UndefinedKeywordTokenException($keyword);
            }
            return constant($keyword);
        }, $this->getKeywordsToCheck());
    }