NoReverseMatch at /shop/cart/

[sdnnet3]

NoReverseMatch

Reverse for 'cart_add' with arguments '('',)' not found. 1 pattern(s) tried: ['shop\/cart\/add/(?P<product_id>\d+)/$']

in cart details:
return redirect('cart:cart_detail')
def cart_detail(request):
cart = Cart(request)
for item in cart:
item['update_quantity_form'] = CartAddProductForm(initial={'quantity': item['quantity'], 'update': True})
return render(request, 'cart/detail.html', {'cart': cart}) ...
▶ Local vars

[sdnnet3]

Wanted to add that this popped up when I upgraded to Dango 2.1.7

[miazigoo]

a'u find u error?
i heve it's too