Django Python

for post in Post.objects.all():
    print(post.author.name)

posts = Post.objects.select_related("author")

for post in posts:
    print(post.author.name)

def create_order(request):
    user = request.user
    items = request.data['items']
    total = 0
    for item in items:
        product = Product.objects.get(id=item['id'])
        total += product.price * item['qty']
    order = Order.objects.create(user=user, total=total)
    ...

# services/order_service.py
def create_order(user, items):
    total = calculate_total(items)
    return Order.objects.create(user=user, total=total)

# views.py
def create_order_view(request):
    order = create_order(request.user, request.data['items'])
    return Response({"id": order.id})