old_contents: from __future__ import unicode_literals
  
  from django.db import models
  from django.db.models import CASCADE
  from django.utils.encoding import python_2_unicode_compatible
  
  
  @python_2_unicode_compatible
  class Foo(models.Model):
      a = models.IntegerField()
      b = models.CharField(max_length=255)
  
      def __str__(self):
          return 'Foo(%s, %s)' % (self.a, self.b)
  
  
  class Bar(models.Model):
      foo = models.ForeignKey(Foo, on_delete=CASCADE)
      c = models.BooleanField()
  
  
  class Baz(models.Model):
      foo = models.ManyToManyField(Foo)
  
new_contents: from __future__ import unicode_literals
  
  from django.db import models
  from django.db.models import CASCADE
  from django.utils.encoding import python_2_unicode_compatible
  
  
  @python_2_unicode_compatible
  class Foo(models.Model):
      a = models.IntegerField()
      b = models.CharField(max_length=255)
  
      def __str__(self):
          return 'Foo(%s, %s)' % (self.a, self.b)
  
      class Meta:
          ordering = ('pk',)
  
  
  class Bar(models.Model):
      foo = models.ForeignKey(Foo, on_delete=CASCADE)
      c = models.BooleanField()
  
      class Meta:
          ordering = ('pk',)
  
  
  class Baz(models.Model):
      foo = models.ManyToManyField(Foo)
  
      class Meta:
          ordering = ('pk',)
  
subject: Fix warnings during tests