old_contents: from __future__ import unicode_literals
  import sys
  
  from django.db import models
  
  from ..models import PolymorphicModel
  
  
  class Animal(PolymorphicModel):
      name = models.CharField(max_length=255)
  
      class Meta:
          app_label = 'polymodels'
          ordering = ('id',)
  
      def __str__(self):
          return self.name
  
      if not sys.version_info[0] == 3:
          __unicode__ = __str__
          __str__ = lambda self: self.__unicode__().encode('utf-8')
  
  
  class Mammal(Animal):
      class Meta:
          app_label = 'polymodels'
  
  
  class Monkey(Mammal):
      class Meta:
          app_label = 'polymodels'
  
  
  class Reptile(Animal):
      length = models.SmallIntegerField()
  
      class Meta:
          app_label = 'polymodels'
          abstract = True
          ordering = ('id',)
  
  
  class Snake(Reptile):
      class Meta:
          app_label = 'polymodels'
  
  
  class BigSnake(Snake):
      class Meta:
          app_label = 'polymodels'
          proxy = True
  
  
  class HugeSnake(BigSnake):
      class Meta:
          app_label = 'polymodels'
          proxy = True
  
new_contents: from __future__ import unicode_literals
  import sys
  
  from django.db import models
  
  from ..models import PolymorphicModel
  
  
  class Animal(PolymorphicModel):
      name = models.CharField(max_length=255)
  
      class Meta:
          app_label = 'polymodels'
          ordering = ('id',)
  
      def __str__(self):
          return self.name
  
      if not sys.version_info[0] == 3:
          __unicode__ = __str__
          __str__ = lambda self: self.__unicode__().encode('utf-8')
  
  
  class Mammal(Animal):
      class Meta:
          app_label = 'polymodels'
  
  
  class Monkey(Mammal):
      class Meta:
          app_label = 'polymodels'
  
  
  class Reptile(Animal):
      length = models.SmallIntegerField()
  
      class Meta:
          app_label = 'polymodels'
          abstract = True
          ordering = ('id',)
  
  
  class Snake(Reptile):
      class Meta:
          app_label = 'polymodels'
          ordering = ('id',)
  
  
  class BigSnake(Snake):
      class Meta:
          app_label = 'polymodels'
          proxy = True
  
  
  class HugeSnake(BigSnake):
      class Meta:
          app_label = 'polymodels'
          proxy = True
  
subject: Make sure to define an ordering on all querie test models