IndexError: list index out of range

def rooms(request):
    form = RoomsFilterForm()
    room_query_set = Room.objects.all()
    is_found = False
 
    context = {
        'form': form,
        'room_list': room_query_set,
        'is_found': is_found,
 
    }
 
    if request.method == 'POST' and request.POST.get('findRoom') == 'find':
        form = RoomsFilterForm(request.POST)
        context['form'] = form
 
        if form.is_valid():
            available_rooms = filter_rooms(form) # В этой строке
            context['lux_rooms'] = available_rooms.filter(comfortability__exact='lux')
            context['semi_lux_rooms'] = available_rooms.filter(comfortability__exact='semi-lux')
            context['standard_rooms'] = available_rooms.filter(comfortability__exact='standard')
            context['room_list'] = available_rooms
            context['is_found'] = True
 
    if request.method == 'POST' and request.POST.get('orderRoom'):
        ordered_room_number = request.POST.get('orderRoom')
        basket = Basket.objects.last()
        date_from = basket.date_from
        date_to = basket.date_to
        user = get_user(request)
        if user.id:
            order = Order(customer=user,
                          check_in_date=date_from,
                          check_out_date=date_to,
                          ordered_rooms=Room.objects.get(number__exact=ordered_room_number),
                          )
            order.save()
            print('order saved')
            Basket.delete(Basket.objects.last())
            messages.success(request, "Ваш заказ успешно создан", extra_tags='order_created')
        else:
            messages.warning(request, "Для заказа комнаты вам необходимо авторизоваться", extra_tags='authorize')
 
    return render(request, template_name='home/static/room_list.html', context=context)

def filter_rooms(form):
    basket = Basket(  # temporarily stores user's checkout and checkin date
        date_from=form.cleaned_data['date_from'],
        date_to=form.cleaned_data['date_to']
    )
    basket.save()
 
    not_ordered_rooms = list(zip(*Room.objects.filter(
        order__isnull=True,
        capacity__exact=form.cleaned_data['capacity'])
                                 .values_list('number')))[0]
    ordered_rooms = list(zip(*Room.objects.filter(  # И в этой строке
        order__isnull=False,
        capacity__exact=form.cleaned_data['capacity']).values_list('number')))[0]
    available_rooms = list(not_ordered_rooms)
 
    if ordered_rooms:
        for room in ordered_rooms:
            closest_check_out_date = Order.objects.filter(ordered_rooms_id=int(room)).filter(
                check_out_date__lte=form.cleaned_data['date_to']).last()
            closest_check_in_date = Order.objects.filter(ordered_rooms_id=int(room)).filter(
                check_in_date__gte=form.cleaned_data['date_from']).last()
 
            if closest_check_in_date and closest_check_out_date:
                if closest_check_in_date.check_in_date >= form.cleaned_data['date_to'] \
                        and closest_check_out_date.check_out_date <= form.cleaned_data['date_from']:
                    available_rooms.append(room)
            if not closest_check_out_date:
                if closest_check_in_date.check_in_date >= form.cleaned_data['date_to']:
                    available_rooms.append(room)
            if not closest_check_in_date:
                if closest_check_out_date.check_out_date <= form.cleaned_data['date_from']:
                    available_rooms.append(room)
 
    return Room.objects.filter(number__in=available_rooms)