  
  
  class Content(models.Model):
      nodes = GenericRelation(Node)
      related_obj = models.ForeignKey('Related', on_delete=models.CASCADE)
  
  
  class Related(models.Model):
      pass
  
 
</s> remove     custom = models.ForeignKey(CustomPk)
 </s> add     custom = models.ForeignKey(CustomPk, models.CASCADE) </s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE) </s> remove     title = models.ForeignKey(Title)
 </s> add     title = models.ForeignKey(Title, models.CASCADE) </s> remove     a1 = models.ForeignKey('lookuperror_a.A1')
 </s> add     a1 = models.ForeignKey('lookuperror_a.A1', models.CASCADE) </s> remove     a1 = models.ForeignKey('lookuperror_a.A1')
 </s> add     a1 = models.ForeignKey('lookuperror_a.A1', models.CASCADE)
    related_obj = models.ForeignKey('Related', models.CASCADE)
  
  
  class Content(models.Model):
      nodes = GenericRelation(Node)
    related_obj = models.ForeignKey('Related', models.CASCADE)
  
  
  class Related(models.Model):
      pass
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/generic_relations_regress/models.py