old_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.db import models
  from django.utils.encoding import python_2_unicode_compatible
  
  
  @python_2_unicode_compatible
  class Category(models.Model):
      name = models.CharField(max_length=255)
  
      def __unicode__(self):
          return unicode(self.name)
  
      def __str__(self):
          return self.name
  
  
  @python_2_unicode_compatible
  class Author(models.Model):
      name = models.CharField(max_length=255)
  
      def __unicode__(self):
          return unicode(self.name)
  
      def __str__(self):
          return self.name
  
  
  @python_2_unicode_compatible
  class Book(models.Model):
      name = models.CharField(max_length=255)
      descn = models.TextField(blank=True)
      price = models.FloatField(null=True, blank=True)
      is_active = models.BooleanField(default=True)
  
      category = models.ForeignKey(Category, null=True, blank=True)
      authors = models.ManyToManyField(Author, blank=True)
  
      class Meta:
          ordering = ["name"]
          permissions = (
              ("sft_mgr_book", "manager book"),
          )
  
      def __unicode__(self):
          return unicode(self.name)
  
      def __str__(self):
          return self.name
  
new_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.db import models
  from django.utils.encoding import python_2_unicode_compatible
  
  
  @python_2_unicode_compatible
  class Category(models.Model):
      name = models.CharField(max_length=255)
  
      def __unicode__(self):
          return unicode(self.name)
  
      def __str__(self):
          return self.name
  
  
  @python_2_unicode_compatible
  class Author(models.Model):
      name = models.CharField(max_length=255)
  
      def __unicode__(self):
          return self.name
  
      def __str__(self):
          return self.name
  
  
  @python_2_unicode_compatible
  class Book(models.Model):
      name = models.CharField(max_length=255)
      descn = models.TextField(blank=True)
      price = models.FloatField(null=True, blank=True)
      is_active = models.BooleanField(default=True)
  
      category = models.ForeignKey(Category, null=True, blank=True)
      authors = models.ManyToManyField(Author, blank=True)
  
      class Meta:
          ordering = ["name"]
          permissions = (
              ("sft_mgr_book", "manager book"),
          )
  
      def __unicode__(self):
          return self.name
  
      def __str__(self):
          return self.name
  
subject: remove unicode