      content = models.TextField()
      created = models.DateTimeField(auto_now_add=True)
      slug = models.SlugField(editable=False, default='')
  
      class Meta:
          ordering = ('created',)
  
      @models.permalink
      def get_absolute_url(self):
          return ('blog-post', (), {'key': self.key})
  
      @property
      @models.permalink
      def comments_url(self):
          """Link to a resource which lists all comments for this blog post."""
          return ('comments', (), {'blogpost': self.key})
  
      def __unicode__(self):
          return self.title
  
      def save(self, *args, **kwargs):
          self.slug = slugify(self.title)
          super(self.__class__, self).save(*args, **kwargs)
          for obj in self.__class__.objects.order_by('-pk')[MAX_POSTS:]:
              obj.delete()
 
</s> remove     class Meta:
        ordering = ('created',)

    @models.permalink
    def get_absolute_url(self):
        return ('comment', (), {'blogpost': self.blogpost.key, 'id': self.id})
    
    @property
    @models.permalink
    def blogpost_url(self):
        """Link to the blog post resource which this comment corresponds to."""
        return ('blog-post', (), {'key': self.blogpost.key})
        
 </s> add  </s> remove         for obj in self.__class__.objects.order_by('-pk')[MAX_POSTS:]:
 </s> add         for obj in self.__class__.objects.order_by('-created')[MAX_POSTS:]: </s> remove     
    class Meta:
        ordering = ('created',)
 </s> add  </s> remove         """For the purposes of the sandbox, limit the maximum number of stored models."""
 </s> add         """
        For the purposes of the sandbox limit the maximum number of stored models.
        """ </s> remove             MyModel.objects.all()[0].delete()
    
    @models.permalink
    def get_absolute_url(self):
        return ('my-model-resource', (self.pk,))
 </s> add             MyModel.objects.all().order_by('-created')[0].delete()

      content = models.TextField()
      created = models.DateTimeField(auto_now_add=True)
      slug = models.SlugField(editable=False, default='')
  
















      def save(self, *args, **kwargs):
          self.slug = slugify(self.title)
          super(self.__class__, self).save(*args, **kwargs)
          for obj in self.__class__.objects.order_by('-pk')[MAX_POSTS:]:
              obj.delete()
keep keep keep keep replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Fixing some of the last blocking issues 
examples/blogpost/models.py