update
I apologise for yet another simple Django question but I cannot find what I'm after.
Project: Blog I'm trying to URL design to the app using Django 2.0
I apologise for yet another simple Django question but I cannot find what I'm after.
Project: Blog I'm trying to URL design to the app using Django 2.0
 
    
     
    
    Django 2.0 adds the new path function for urls : https://docs.djangoproject.com/fr/2.0/ref/urls/#path
path doesn't use regex anymore. 
You have two solutions
1) Use path and change the url pattern to new django format
from django.urls import path 
urlpatterns = [
    url('/post/<int:pk>/', ...)
]
2) Keep you regex and use re_path
from django.urls import re_path
urlpatterns = [
    re_path('^/post/(?<pk>[0-9]+)/$', ...)
]
Note that using url function is still possible but will be likely be deprecated in a next version. It has been renamed into re_path in Django 2.0
 
    
    update you urls.py file.
you need to import view_post in urls.py file
from blog.views import view_post
#from appname.file.py import (class/func)name
As you are using view_post in urls.py so you also need to import it in that file.
 
    
    