public function setAuthor(Author $author)
    {
        $this->attachment['author_name'] = $author;

        if ($author->hasIcon()) {
            $this->attachment['author_icon'] = $author->getIcon();
        }

        if ($author->hasLink()) {
            $this->attachment['author_link'] = $author->getLink();
        }

        return $this;
    }