title: django.template.library.InvalidTemplateLibrary: Invalid template library specified
body: <p>I am trying to build a Blog application. Ran makemigrations and migrate and also created superuser. But I am getting below error while running the server.</p>
  
  <p>django.template.library.InvalidTemplateLibrary: Invalid template library specified. ImportError raised when trying to load 'blog.templatetags.blog_tags': cannot import name 'POST' from 'blog.models'</p>
  
  <p>Please help me....
  My models.py file is </p>
  
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  from django.utils import timezone
  from django.urls import reverse
  # Create your models here.
  
  class CustomManager(models.Manager):
      def get_queryset(self):
          return super().get_queryset().filter(status='published')
  
  
  from taggit.managers import TaggableManager
  
  class Post(models.Model):
      STATUS_CHOICES=(('draft','Draft'),('published','Published')) 
      title=models.CharField(max_length=256)
      slug=models.SlugField(max_length=264,unique_for_date='publish') 
      author=models.ForeignKey(User,related_name='blog_posts',on_delete=models.DO_NOTHING)
      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=CustomManager()
      tags=TaggableManager()  
      class Meta:
          ordering=('-publish',) 
      def __str__(self):
          return self.title 
  
      def get_absolute_url(self):  
          return reverse('post_detail',args=[self.publish.year,self.publish.strftime('%m'),self.publish.strftime('%d'),self.slug])
  
  class Comment(models.Model):
      post=models.ForeignKey(Post,related_name='comments',on_delete=models.DO_NOTHING)
      name=models.CharField(max_length=40)
      email=models.EmailField()
      body=models.TextField()
      created=models.DateTimeField(auto_now_add=True)  
      updated=models.DateTimeField(auto_now=True)      
      active=models.BooleanField(default=True)         
      class Meta:
          ordering=('-created',)
      def __str__(self):
          return 'Commented by {} on {}'.form(self.name,self.post)
  </code></pre>