public function getRealAuthor($author)
    {
        if ($this->isAuthorIgnored($author)) {
            return null;
        }

        if ($this->isAlias($author)) {
            $author = $this->mapping[$this->arrayKey($author)];
        }

        if ($this->isAuthorIgnored($author)) {
            return null;
        }

        return $author;
    }