Mezzanine + Cartridge 'Cart' instance needs to have a primary key value

Good afternoon. I just installed the “Mezzanine + cartridge”, to see its capabilities and got an error. Please help me solve this.

Django Version: 4.1
Python Version: 3.8.10
Installed Applications:
('mezzanine.boot',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.redirects',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.sitemaps',
'django.contrib.messages',
'mezzanine.conf',
'mezzanine.core',
'mezzanine.generic',
'mezzanine.pages',
'cartridge.shop',
'mezzanine.blog',
'mezzanine.forms',
'mezzanine.galleries',
'filebrowser_safe',
'grappelli_safe',
'django.contrib.admin',
'django.contrib.staticfiles',
'django_comments')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'cartridge.shop.middleware.ShopMiddleware',
'mezzanine.core.request.CurrentRequestMiddleware',
'mezzanine.core.middleware.RedirectFallbackMiddleware',
'mezzanine.core.middleware.AdminLoginInterfaceSelectorMiddleware',
'mezzanine.core.middleware.SitePermissionMiddleware',
'mezzanine.pages.middleware.PageMiddleware')

Template error:
In template /home/vlad/anycoderu/cartridge/cartridge/shop/templates/shop/includes/user_panel.html, error at line 5
'Cart' instance needs to have a primary key value before this relationship can be used.
1 : {% load i18n shop_tags mezzanine_tags %}
2 : {% spaceless %}
3 : <a href="{% url "shop_cart" %}">
4 :
5 : {% blocktrans count request.cart.total_quantity as cart_quantity %} 1 item{% plural %}{{ cart_quantity }} items{% endblocktrans %}
6 : {% trans "in cart" %}:
7 : {{ request.cart.total_price|currency }}

8 : {% if request.cart.total_quantity != 0 %}
9 : <a href="{% url "shop_checkout" %}" class="btn btn-primary">
10 : {% if request.session.order.step %}{% trans "Return to Checkout" %}{% else %}{% trans "Go to Checkout" %}{% endif %}
11 :

12 : {% endif %}
13 : {% if settings.SHOP_USE_WISHLIST %}
14 : <a href="{% url "shop_wishlist" %}" class="btn-wishlist">
15 :

Traceback (most recent call last):
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/core/handlers/exception.py", line 55, in inner
response = get_response(request)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/core/handlers/base.py", line 220, in _get_response
response = response.render()
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/response.py", line 114, in render
self.content = self.rendered_content
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/response.py", line 92, in rendered_content
return template.render(context, self._request)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/backends/django.py", line 62, in render
return self.template.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 175, in render
return self._render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 167, in _render
return self.nodelist.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/loader_tags.py", line 157, in render
return compiled_parent._render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 167, in _render
return self.nodelist.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/mezzanine/template/init.py", line 95, in render
args = (self.nodelist.render(context), context, token)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/loader_tags.py", line 208, in render
return template.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 177, in render
return self._render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 167, in _render
return self.nodelist.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/defaulttags.py", line 322, in render
return nodelist.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/loader_tags.py", line 208, in render
return template.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 177, in render
return self._render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 167, in _render
return self.nodelist.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/defaulttags.py", line 415, in render
return strip_spaces_between_tags(self.nodelist.render(context).strip())
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in render
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 1005, in
return SafeString("".join([node.render_annotated(context) for node in self]))
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 966, in render_annotated
return self.render(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/templatetags/i18n.py", line 160, in render
count = self.counter.resolve(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 715, in resolve
obj = self.var.resolve(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 847, in resolve
value = self._resolve_lookup(context)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/template/base.py", line 914, in _resolve_lookup
current = current()
File "/home/vlad/anycoderu/cartridge/cartridge/shop/models.py", line 643, in total_quantity
return sum(item.quantity for item in self)
File "/home/vlad/anycoderu/cartridge/cartridge/shop/models.py", line 610, in iter
self._cached_items = self.items.all()
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/db/models/fields/related_descriptors.py", line 596, in get
instance_cache[key] = self.related_manager_cls(instance)
File "/home/vlad/anycoderu/anycodenv/lib/python3.8/site-packages/Django-4.1-py3.8.egg/django/db/models/fields/related_descriptors.py", line 634, in init
raise ValueError(

Exception Type: ValueError at /
Exception Value: 'Cart' instance needs to have a primary key value before this relationship can be used.


Made changes to the code as in the picture and it worked! I’m happy!