old_contents: from __future__ import absolute_import
  
  from django.db import models
  
  
  class Pet(models.Model):
      name = models.CharField(max_length=30)
  
  
  class Film(models.Model):
      reporters = models.ManyToManyField('Reporter',
                                         related_name='films')
  
  
  class Reporter(models.Model):
      first_name = models.CharField(max_length=30)
      last_name = models.CharField(max_length=30)
      email = models.EmailField()
      pets = models.ManyToManyField('self')
  
      def __str__(self):              # __unicode__ on Python 2
          return "%s %s" % (self.first_name, self.last_name)
  
  
  class Article(models.Model):
      headline = models.CharField(max_length=100)
      pub_date = models.DateField()
      reporter = models.ForeignKey(Reporter, related_name='articles')
  
      def __str__(self):              # __unicode__ on Python 2
          return self.headline
  
      class Meta:
          ordering = ('headline',)
  
new_contents: from __future__ import absolute_import
  
  from django.db import models
  
  
  class Pet(models.Model):
      name = models.CharField(max_length=30)
  
  
  class Film(models.Model):
      reporters = models.ManyToManyField('Reporter',
                                         related_name='films')
  
  
  class Reporter(models.Model):
      first_name = models.CharField(max_length=30)
      last_name = models.CharField(max_length=30)
      email = models.EmailField()
      pets = models.ManyToManyField('self')
  
      def __str__(self):              # __unicode__ on Python 2
          return "%s %s" % (self.first_name, self.last_name)
  
  
  class Article(models.Model):
      headline = models.CharField(max_length=100)
      pub_date = models.DateField()
      reporter = models.ForeignKey(Reporter, related_name='articles')
      lang = models.CharField(max_length=2, help_text='Language', choices=[
          ('es', 'Spanish'),
          ('en', 'English')
      ], default='es')
  
      def __str__(self):              # __unicode__ on Python 2
          return self.headline
  
      class Meta:
          ordering = ('headline',)
  
subject: Improve Django field conversion real-life tests