{% with id=widget.attrs.id %}<ul{% if id %} id="{{ id }}"{% endif %}>{% for group, options, index in widget.optgroups %}{% if group %}
  <li>{{ group }}<ul{% if id %} id="{{ id }}_{{ index }}"{% endif %}>{% endif %}{% for option in options %}
    <li>{% include option.template_name with widget=option %}</li>{% endfor %}{% if group %}
  </ul></li>{% endif %}{% endfor %}
</ul>{% endwith %}