old_contents: from __future__ import unicode_literals
  
  from django.db import models
  
  # Create your models here.
  
new_contents: from __future__ import unicode_literals
  
  from django.db import models
  from django.utils import timezone
  
  # Create your models here.
  
  class Post(models.Model):
      author = models.ForeignKey('auth.User')
      title = models.CharField(max_length=200)
      text = models.TextField()
      created_date = models.DateTimeField(default=timezone.now)
      published_date = models.DateTimeField(blank=True, null=True)
  
      def publish(self):
          self.published_date = timezone.now()
          self.save()
  
      def __str__(self):
          return self.title
subject: Create Post model in model.py