Django template keyword `choice_value` in no longer work in 1.11

Question

There is a multiple checkbox in template, if value contain in render the choice will checked by default. It works well with 1.10.

form.py:

class NewForm(forms.Form):
    project = forms.ModelMultipleChoiceField(
        widget=forms.CheckboxSelectMultiple, 
        queryset=Project.objects.filter(enable=True)
    )

template:

{% for p in form.project %}
<label for="{{ p.id_for_label }}">
    <input type="checkbox" name="{{ p.name }}" id="{{ p.id_for_label }}"
        value="{{ p.choice_value }}"
        {% if p.choice_value|add:"0" in form.project.initial %} checked{% endif %}>
    <p>{{ p.choice_label }}</p>
</label>
{% endfor %}

views.py:

def order_start(request, order_id):
    if request.method == 'POST':
        form = NewForm(request.POST)
        if form.is_valid():
            order.end_time = timezone.now()
            order.save()
            order.project = form.cleaned_data['project']
            order.save()
            return HttpResponsec(order.id)
    else:
        form = NewForm(initial={
            'project': [p.pk for p in order.project.all()],
        })

    return render(request, 'orders/start.html', {'form': form, 'order': orderc})

When I upgrade to Django 1.11, {{ p.name }} and {{ p.choice_value }} return nothing. I know 1.11 has removed choice_value, but how to solve this problem?

1.10 https://docs.djangoproject.com/en/1.10/_modules/django/forms/widgets/
1.11 https://docs.djangoproject.com/en/1.11/_modules/django/forms/widgets/

Answer 1

As @L_S 's comments. I debug with dir(form), all value contained in form.project.data here's the correct code:

{% for choice in form.project %}
<labelc for="{{ choice.id_for_label }}">
    <input type="checkbox" name="{{ choice.data.name }}" id="{{ choice.id_for_label }}" 
    value="{{ choice.data.value }}"{% if choice.data.selected %} checked{% endif %}>
    {{ choice.data.label }}
</label>
{% endfor %}