get_absolute_url creates blank link - django

Question

get_absolute_url doesn't create url. Clicking in title of the post must lead to detail of the post. While I manually create url in address bar as blog/2020/1/3/check-text, it works. What could be the possible problem? Is it something to do with python version?
models.py
from django.db import models
from django.utils import timezone
from django.contrib.auth.models import User
from django.urls import reverse
class PublishedManager(models.Manager):
def get_queryset(self):
return super(PublishedManager, self).get_queryset().filter(status='published')
class Post(models.Model):
STATUS_CHOICES = (
('draft', 'Draft'),
('published', 'Published'),
)
title = models.CharField(max_length=250)
slug = models.SlugField(max_length=250,
unique_for_date='publish')
author = models.ForeignKey(User,
on_delete=models.CASCADE)
body = models.TextField()
publish = models.DateTimeField(default = timezone.now)
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
status = models.CharField(max_length=10,
choices=STATUS_CHOICES,
default='draft')
objects = models.Manager() # the default manager
published = PublishedManager() # our custom manager
class Meta:
ordering = ('-publish',)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('blog:post_detail', args = [
self.publish.year,
self.publish.month,
self.publish.day,
self.slug,
])
views.py
from django.shortcuts import render, get_object_or_404
from django.core.paginator import Paginator, PageNotAnInteger,\
EmptyPage
from django.views.generic import ListView
from .models import Post
from .forms import EmailPostForm
from django.core.mail import send_mail
class PostListView(ListView):
queryset = Post.published.all()
context_object_name = 'posts'
paginate_by = 3
template_name = 'blog/post/list.html'
def post_detail(request, year, month, day, post):
post = get_object_or_404(Post, slug=post,
status='published',
publish__year=year,
publish__month=month,
publish__day=day)
return render(request,
'blog/post/detail.html',
{'post': post})
urls.py
from django.urls import path
from . import views
app_name = 'blog'
urlpatterns = [
path('', views.PostListView.as_view(), name='post_list'),
path('<int:year>/<int:month>/<int:day>/<slug:post>/',
views.post_detail,
name='post_detail'),
path('<int:post_id>/share/',
views.post_share, name='post_share'),
]
list.html
{% extends 'blog/base.html' %}
{% block title %}My Blog{% endblock%}
{% block content %}
<h1>My Blog</h1>
{% for post in posts %}
<h2>
<a href="{{ post.get_absolute_url }}">
{{ post.title }}
</a>
</h2>
<p class="date">
Published {{ post.publish }} by {{ post.author }}
</p>
{{ post.body|truncatewords:30|linebreaks }}
{% endfor %}
<!-- {% include '../pagination.html' with page=posts %} -->
{% include '../pagination.html' with page=page_obj %}
{% endblock %}
detail.html
{% extends 'blog/base.html' %}
{% block title %}{{ post.title }}{% endblock %}
{% block content %}
<h1>{{ post.title }}</h1>
<p class="date">
Published {{ post.publish }} by {{ post.author }}
</p>
{{ post.body|linebreaks }}
<p>
<a href="{% url 'blog:post_share' post.id %}">
Share this post
</a>
</p>
{% endblock %}
see href is empty