          class Band(models.Model):
              name = models.CharField(max_length=50)
  
          class BandMember(models.Model):
              band_ct = models.ForeignKey(ContentType)
              band_id = models.PositiveIntegerField()
              band = UnsavedGenericForeignKey('band_ct', 'band_id')
              first_name = models.CharField(max_length=50)
              last_name = models.CharField(max_length=50)
  
 
</s> remove             band = UnsavedForeignKey(Band)
 </s> add             band = UnsavedForeignKey(Band, models.CASCADE) </s> remove     teacher = models.ForeignKey(Teacher)
 </s> add     teacher = models.ForeignKey(Teacher, models.CASCADE) </s> remove         artist = models.ForeignKey(Musician)
 </s> add         artist = models.ForeignKey(Musician, on_delete=models.CASCADE) </s> remove     related = models.ForeignKey(Secondary)
 </s> add     related = models.ForeignKey(Secondary, models.CASCADE) </s> remove     content_type = models.ForeignKey(ContentType)
 </s> add     content_type = models.ForeignKey(ContentType, models.CASCADE)
            band_ct = models.ForeignKey(ContentType, models.CASCADE)
          class Band(models.Model):
              name = models.CharField(max_length=50)
  
          class BandMember(models.Model):
            band_ct = models.ForeignKey(ContentType, models.CASCADE)
              band_id = models.PositiveIntegerField()
              band = UnsavedGenericForeignKey('band_ct', 'band_id')
              first_name = models.CharField(max_length=50)
              last_name = models.CharField(max_length=50)
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/contenttypes_tests/tests.py