<select name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %}>{% for group_name, group_choices, group_index in widget.optgroups %}{% if group_name %}
  <optgroup label="{{ group_name }}">{% endif %}{% for widget in group_choices %}
  {% include widget.template_name %}{% endfor %}{% if group_name %}
  </optgroup>{% endif %}{% endfor %}
</select>