how do I fix NoReverseMatch error when i trying convert to class base my code?

I have some code and when it executes, it throws a No Reverse Match, saying:

What does this mean, and what can I do about it?

I m trying convert my code to class base and name space for my app.

I have some code and when it executes, it throws a NoReverseMatch, saying:

NoReverseMatch at /dashboard/leads/6/
Reverse for 'delete' with arguments '('',)' not found.
1 pattern(s) tried: ['dashboard/leads/(?P<pk>[0-9]+)/delete/$']

view.py

class LeadDetailView(DetailView):
model = Lead
@method_decorator(login_required)
def dispatch(self, *args, **kwargs):
return super().dispatch(*args, **kwargs)
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['form'] = AddCommentForm()
def get_queryset(self):
queryset = super(LeadDetailView, self).get_queryset()
return queryset.filter(created_by=self.request.user, pk=self.kwargs.get('pk'))
class LeadDeleteView(DeleteView):
model = Lead
success_url = reverse_lazy('leads:list')
@method_decorator(login_required)
def dispatch(self, *args, **kwargs):
return super().dispatch(*args, **kwargs)
def get_queryset(self):
queryset = super(LeadDeleteView, self).get_queryset()
team = self.request.user.userprofile.active_team
return queryset.filter(team=team, pk=self.kwargs.get('pk'))
def get(self, request, *args, **kwargs):
return self.post(request, *args, **kwargs)
class LeadUpdateView(UpdateView):
model = Lead
fields = ('name', 'email', 'description', 'priority', 'status',)
success_url = reverse_lazy('leads:list')
@method_decorator(login_required)
def dispatch(self, *args, **kwargs):
return super().dispatch(*args, **kwargs)
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['title'] = 'Edit lead'
return context
def get_queryset(self):
queryset = super(UpdateView, self).get_queryset()
return queryset.filter(created_by=self.request.user, pk=self.kwargs.get('pk'))

urls.py

from django.urls import path
from . import views
app_name = 'leads'
urlpatterns = [
path('', views.LeadListView.as_view(), name='list'),
path('<int:pk>/', views.LeadDetailView.as_view(), name='detail'),
path('<int:pk>/delete/', views.LeadDeleteView.as_view(), name='delete'),
path('<int:pk>/edit/', views.LeadUpdateView.as_view(), name='edit'),
path('<int:pk>/convert/', views.ConvertToClientView.as_view(), name='convert'),
path('add/', views.LeadCreateView.as_view(), name='add'),
]

{% extends 'core/base.html' %}
{% block title %}{{ lead.name }}{% endblock %}
{% block content %}
<div class="py-4 px-6">
<h1 class="mb-4 text-xl">{{ lead.name }}</h1>
{% if lead.description %}
<p class="font-semibold">Description</p>
<p class="mb-2 "> {{ lead.description }}</p>
{% endif %}
<p class="font-semibold">Priority</p>
<p class="mb-2 ">{{ lead.get_priority_display }}</p>
<p class="font-semibold">Status</p>
<p class="mb-2 ">{{ lead.get_status_display }}</p>
<p class="font-semibold">Created at</p>
<p class="mb-2 ">{{ lead.created_at|date:"M-d-Y H:i" }}</p>
<p class="font-semibold">Modified at</p>
<p class="mb-6 ">{{ lead.modified_at }}</p>
<hr class="my-4">
<form id="lead_delete_form" method="post" action="{% url 'leads:delete' lead.id %}" >
{% csrf_token %}
</form>
<a href="{% url 'leads:convert' lead.id %}" class="py-2 px-4 rounded-xl bg-blue-500 text-white">Convert to client</a>
<a href="{% url 'leads:edit' lead.id %}" class="py-2 px-4 rounded-xl bg-teal-500 text-white">Edit</a>
<a href="#" onclick="document.getElementById('lead_delete_form').submit();" class="py-2 px-4 rounded-xl bg-red-500 text-white">Delete</a>
<hr class="my-4">
<h2 class="text-2xl">Comments</h2>
<form method="get" action=".">
{% csrf_token %}
{{ form.as_p }}
<button class="py-2 px-4 rounded-xl bg-blue-500 text-white">Submit</button>
</form>
<hr class="my-4">
<a href="{% url 'leads:list' %}">Back to Leads</a>
</div>
{% endblock %}

Based on your "urls.py" which requires the pk argument on delete view, the error tells you that the pk argument is not being passed correctly when generating the URL.

To fix this issue, you should ensure that the pk argument is correctly provided to the success_url attribute when using the reverse or reverse_lazy functions.

For example, you can update the success_url attribute in your LeadDeleteView as follows:

success_url = reverse_lazy('leads:detail', kwargs={'pk': self.object.pk})