old_contents: from django.db import models
  from django.contrib.auth.models import User
  
  class BlogPost(models.Model):
      user = models.ForeignKey(User)
      title = models.CharField(max_length = 120)
      text = models.TextField()
      date = models.DateTimeField(auto_now_add = True)
  
  class Comment(models.Model):
      user = models.ForeignKey(User)
      post = models.ForeignKey(BlogPost)
      text = models.TextField()
      date = models.DateTimeField(auto_now_add = True)
  
new_contents: from django.db import models
  from django.contrib.auth.models import User
  
  class BlogPost(models.Model):
      user = models.ForeignKey(User)
      title = models.CharField(max_length = 120)
      text = models.TextField()
      date = models.DateTimeField(auto_now_add = True)
  
      def __unicode__(self):
          return self.title
  
  class Comment(models.Model):
      user = models.ForeignKey(User)
      post = models.ForeignKey(BlogPost)
      text = models.TextField()
      date = models.DateTimeField(auto_now_add = True)
  
      def __unicode__(self):
          return unicode("%s: %s" % (self.post, self.text[:60]))
  
subject: Add __unicode__ methods to BlogPost and Comment models