basic-flask-site/templates/parts/author_list.html

<div class="authors" >
    <ul>
    {% for author in users.get_all() %}
        <li>
            <a href="{{ url_for('get_author', author_id=author.id) }}">
                {{ author.username }} |
            </a>
        </li>
    {% endfor %}
    </ul>

</div>