old_contents: from __future__ import unicode_literals
  
  from django.core.urlresolvers import reverse
  from django.db import models
  import generic_scaffold
  
  class Book(models.Model):
      title = models.CharField(max_length=128)
      author = models.CharField(max_length=128)
      category = models.CharField(max_length=32)
  
      def get_absolute_url(self):
          return reverse(self.detail_url_name, args=[self.id])
  
new_contents: from __future__ import unicode_literals
  
  try:
      from django.core.urlresolvers import reverse
  except ModuleNotFoundError:
      from django.urls import reverse
  
  from django.db import models
  import generic_scaffold
  
  class Book(models.Model):
      title = models.CharField(max_length=128)
      author = models.CharField(max_length=128)
      category = models.CharField(max_length=32)
  
      def get_absolute_url(self):
          return reverse(self.detail_url_name, args=[self.id])
  
      def __str__(self):
          return '{0} {1} {2}'.format(self.title, self.author, self.category)
  
subject: Add support for django 2 to example project