MY add to cart button not save user preferred size with it in django no javascript is used

I want to fetch user selected size with the quantity and product but I don’t understand how to do that any how idea to achieve that i try to look documentation but didn’t find one any idea how to do that

my views.py for add to cart

class Product_detail(View):
    def get(self, request, item_id,):
        item = Item.objects.filter(id=item_id)
        category_list = Categories.objects.all()
        items = Item.objects.all()
        print(item)
        return render (request, 'product_detail.html',{"items" : item, 'category_list': category_list, 'item': items })

    def post(self, request, item_id):
        item = request.POST.get('item')
        size = request.POST.get('Size')
        cart = request.session.get('cart')
        if cart:
            cart[item] = 1
        else:
            cart = {}
            cart[item] = 1
        request.session['cart'] = cart
        print(request.session['cart'])
        return redirect('products:detail', item_id=item_id)

my html code

<form method="POST" action="#{{ item.id }}">
                  {% csrf_token %}
                  <input type="text" value="{{item.id}}" hidden name="item">
                  <div class="prefer">
                  <label for="Size" style="font-size: 20px; font-weight:500;">Select Size:</label>
                  <select name="Size" id="size">
                    <option value="S">S</option>
                    <option value="M">M</option>
                    <option value="L">L</option>
                    <option value="XL">XL</option>
                    <option value="2XL">2XL</option>
                  </select>
                  </div>
                  <button class="btn btn-outline-primary add" type="submit" style="float: left;">Add To Cart</button>
                </form>

right now I am only able to fetch its item id and quantity
and look like this {‘1’: 1} instead i want it t be {‘Id’: ‘Size’ : ‘Quantity’} all i want to know how to assign a size if a user choose any size basically i want to request size in cart to with its id an an quantity

any suggestion will be appreciated

thank you

previously used code

def post(self, request, item_id):
        item = request.POST.get('item')
        size = request.POST.get('Size')
        cart = request.session.get('cart')
        if cart:
            quantity = cart.get(item)
            if quantity:
                cart[item] = quantity+1
            else:
                cart[item] = 1
        else:
            cart = {}
            cart[item] = 1
        request.session['cart'] = cart
        print(request.session['cart'])
        return redirect('products:detail', item_id=item_id)

• for every item you are assigning 1 in cart cart[item] = 1 here we needs size which you are getting from post cart[item] = size
• if you want to store each item separately even though user has selected the same item twice then you need to change the cart to list
• for maintaining quantity {'1': 'M'} , {'1': 'L'} or {'id' , 'size', 'quantity'} structure would not work

# structure
{
  product_id: {
    product_size: product_quantity
  }
}

# example
{
  1: {
    'L': 1,
    'M': 2,
  }
}

def post(self, request, item_id):
  item = request.POST.get('item')
  size = request.POST.get('Size')
  cart = request.session.get('cart', None)
  if cart == None:
    cart = {}
  cart_item = cart.get(item, None)
  if cart_item == None:
    cart[item] = {
      size: 1,
    }
  elif cart_item.get(size, None) == None:
    cart[item][size] = 1
  else:
    cart[item][size] += 1
  request.session['cart'] = cart
  print(request.session['cart'])
  return redirect('products:detail', item_id=item_id)