Реверс для 'cart_add' с аргументами '(' ',)' не найден. 1 шаблон (ов) пробовал: ['cart / add / (? P [0-9] +) / $ ']

Question

Я создавал онлайн-библиотеку, когда я сделал свое «приложение корзины», я получил это сообщение об ошибке

Реверс для 'cart_add' с аргументами '(' ',)' не найден. Попробован 1 шаблон (ов): ['cart / add / (? P [0-9] +) / $']

Главная страница (http://127.0.0.1: 8000 ) отображается нормально Как только я нажимаю на название книги, появляется эта ошибка.

вот мой шнур приложения корзины, пожалуйста, спасите меня мольбы ....... T_T

from django.conf import settings
from library.models import Book
class Cart(object):
    def __init__(self, request):
        self.session = request.session
        cart = self.session.get(settings.CART_SESSION_ID)
        if not cart:
            cart = self.session[settings.CART_SESSION_ID] = {}
            self.cart = cart

    def add(self, book, quantity=1, update_quantity=False):

        book_id = str(book.id)
        if book_id not in self.cart:
            self.cart[book_id] = {'quantity': 0}
        if update_quantity:
            self.cart[book_id]['quantity'] = quantity
        else:
            self.cart[book.id]['quantity'] += quantity
        self.save()

    def remove(self, book):
        book_id = str(book.id)
        if book_id in self.cart:
            del self.cart[book_id]
            self.save()

    def save(self):
        self.session[settings.CART_SESSION_ID] = self.cart
        self.session.modified = True

    def __iter__(self):
        book_ids = self.cart.keys()
        books = Book.objects.filter(id__in=book_ids)
        for book in books:
            self.cart[str(book.id)]['book'] = book

    def __len__(self):
        return sum(item['quantity'] for item in self.cart.values())

    def clear(self):
        self.session[settings.CART_SESSION_ID] = {}
        self.session.modified = True

from django import forms

PRODUCT_QUANTITY_CHOICES = [(i, str(i)) for i in range(1, 21)]


class CartAddProductForm(forms.Form):
    quantity = forms.TypedChoiceField(choices=PRODUCT_QUANTITY_CHOICES,
                                      coerce=int)
    update = forms.BooleanField(required=False,
                                initial=False,
                                widget=forms.HiddenInput)

from django.urls import path
from . import views
app_name = 'cart'

urlpatterns = [
    path('', views.cart_detail, name='cart_detail'),
    path('add/<int:book_id>/', views.cart_add, name='cart_add'),
    path('remove/<int:book_id>/', views.cart_remove, name='cart_remove'),
]

from django.shortcuts import render, redirect, get_object_or_404
from django.views.decorators.http import require_POST
from library.models import Book
from .cart import Cart
from .forms import CartAddProductForm


@require_POST
def cart_add(request, book_id):
    cart = Cart(request)
    book = get_object_or_404(Book, id=book_id)
    form = CartAddProductForm(request.POST)
    if form.is_valid():
        cd = form.cleaned_data
        cart.add(book=book,
                 quantity=cd['quantity'],
                 update_quantity=cd['update'])
    return redirect('cart:cart_detail')


def cart_remove(request, book_id):
    cart = Cart(request)
    book = get_object_or_404(Book, id=book_id)
    cart.remove(book)
    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})

{% extends "library/base.html" %}
{% load static %}

{% block title %}
    Your book cart
{% endblock %}

{% block content %}
    <h1>Your book cart</h1>
    <table class="cart">
        <thead>
            <tr>
                <th>Image</th>
                <th>Book</th>
                <th>Quantity</th>
                <th>Remove</th>
            </tr>
        </thead>
        <tbody>
        {% for item in cart %}
            {% with book=item.book %}
            <tr>
                <td>
                    <a href="{{ book.get_absolute_url }}">
                        <img src="{% if book.image_url %}{{ book.image_url }}{% else %}{% static 'library/no_image.png' %}{% endif %}">
                    </a>
                </td>
                <td>{{ book.title }}</td>
                <td>
                    <form action="{% url 'cart:cart_add' book.id %}" method="post">
                        {{ item.update_quantity_form.quantity }}
                        {{ item.update_quantity_form.update }}
                        <input type="submit" value="Update">
                        {% csrf_token %}
                    </form>
                </td>
                <td><a href="{% url 'cart:cart_remove' book.id %}">Remove</a></td>
            </tr>
            {% endwith %}
        {% endfor %}
        <tr class="total">
            <td>Total</td>
            <td colspan="4"></td>
        </tr>
        </tbody>
    </table>
    <p class="text-right">
        <a href="{% url 'library:book_list' %}" class="button light">Continue browsing books</a>

    </p>
{% endblock %}

from django.db import models
from django.urls import reverse


class Book(models.Model):
    title = models.CharField(max_length=120)
    author = models.CharField(max_length=120)
    publisher = models.CharField(max_length=120)
    image_url = models.CharField(max_length=100000, blank=True)
    slug = models.SlugField(max_length=200, db_index=True)
    stock = models.PositiveIntegerField()
    timestamp = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)
    active = models.BooleanField(default=True)
    available = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ('-created',)
        index_together = (('id', 'slug'),)

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('library:book_detail', args=[self.id, self.slug])