{% for c1 in service_form.sub_items %}
  • {{ c1.id_display }} {{ c1.name }}
      {% for c2 in c1.sub_items %}
    • {{ c2.id_display }} {{ c2.name }}
        {% for a in c2.sub_items %}
      • {{ a.id_display }} {{ a.name }}
      • {% endfor %}
    • {% endfor %}
  • {% endfor %}