{% with id=widget.attrs.id %}
<div class="btn-group btn-group-toggle" role="group">    
    {% for group, options, index in widget.optgroups %}  
        {% for option in options %}
            <input type="radio" class="btn-check" name="{{option.name}}" id="{{id}}_{{option.index}}" autocomplete="off" 
            value="{{option.value}}" required>
            <label class="btn btn-outline-primary" for="{{id}}_{{option.index}}">{{option.label}}</label>
        {% endfor %}
    {% endfor %}
</div>
{% endwith %}