old_contents: from django.db import models
  from django.contrib.contenttypes import generic
  from django.contrib.contenttypes.models import ContentType
  
  from ...models import WellBase, WellNodeBase, WellTypeBase, WellType
  
  
  class Content(models.Model):
      title = models.CharField(max_length=100)
  
      def __unicode__(self):
          return self.title
  
  
  class Story(Content):
      body = models.TextField()
  
  
  class StoryChild(Story):
      comment = models.CharField(max_length=100)
  
  
  class Image(Content):
      url = models.URLField()
  
  
  class OddNode(models.Model):
      foo = models.ForeignKey(ContentType)
      bar = models.PositiveIntegerField()
      baz = generic.GenericForeignKey('foo', 'bar')
  
  
  class MissingFieldWell(WellBase):
      # missing the `type` field
      pass
  
  
  class MissingFieldWellNode(WellNodeBase):
      # missing the `well` field
      pass
  
  
  class NewWell(WellBase):
      type = models.ForeignKey(WellType)
  
  
  class NewNode(WellNodeBase):
      well = models.ForeignKey(NewWell, related_name="nodes")
  
  
  class WrongRelationWell(WellBase):
      type = models.ForeignKey(WellType)
  
  
  class WrongRelationNode(WellNodeBase):
      well = models.ForeignKey(WrongRelationWell, related_name="foo")
  
  
  class DifferentWellType(WellTypeBase):
      pass
  
  
  class DifferentWell(WellBase):
      type = models.ForeignKey(DifferentWellType)
  
new_contents: from django.db import models
  from django.contrib.contenttypes import generic
  from django.contrib.contenttypes.models import ContentType
  
  from ...models import WellBase, NodeBase, WellTypeBase, WellType
  
  
  class Content(models.Model):
      title = models.CharField(max_length=100)
  
      def __unicode__(self):
          return self.title
  
  
  class Story(Content):
      body = models.TextField()
  
  
  class StoryChild(Story):
      comment = models.CharField(max_length=100)
  
  
  class Image(Content):
      url = models.URLField()
  
  
  class OddNode(models.Model):
      foo = models.ForeignKey(ContentType)
      bar = models.PositiveIntegerField()
      baz = generic.GenericForeignKey('foo', 'bar')
  
  
  class MissingFieldWell(WellBase):
      # missing the `type` field
      pass
  
  
  class MissingFieldWellNode(NodeBase):
      # missing the `well` field
      pass
  
  
  class NewWell(WellBase):
      type = models.ForeignKey(WellType)
  
  
  class NewNode(NodeBase):
      well = models.ForeignKey(NewWell, related_name="nodes")
  
  
  class WrongRelationWell(WellBase):
      type = models.ForeignKey(WellType)
  
  
  class WrongRelationNode(NodeBase):
      well = models.ForeignKey(WrongRelationWell, related_name="foo")
  
  
  class DifferentWellType(WellTypeBase):
      pass
  
  
  class DifferentWell(WellBase):
      type = models.ForeignKey(DifferentWellType)
  
subject: Fix import issue (oops)