      pass
  
  
  class Profile(models.Model):
      collection = models.ForeignKey(ProfileCollection, blank=True, null=True)
      first_name = models.CharField(max_length=100)
      last_name = models.CharField(max_length=100)
 
</s> remove     collection = models.ForeignKey(TitleCollection, blank=True, null=True)
 </s> add     collection = models.ForeignKey(TitleCollection, models.SET_NULL, blank=True, null=True) </s> remove     alfa = models.ForeignKey(Alfa, null=True)
    bravo = models.ForeignKey(Bravo, null=True)
 </s> add     alfa = models.ForeignKey(Alfa, models.SET_NULL, null=True)
    bravo = models.ForeignKey(Bravo, models.SET_NULL, null=True) </s> remove     person = models.ForeignKey(Person, primary_key=True)
 </s> add     person = models.ForeignKey(Person, models.CASCADE, primary_key=True) </s> remove         artist = models.ForeignKey(Musician)
 </s> add         artist = models.ForeignKey(Musician, on_delete=models.CASCADE) </s> remove     author = models.ForeignKey(Author, related_name='books', null=True)
 </s> add     author = models.ForeignKey(Author, models.SET_NULL, related_name='books', null=True)
    collection = models.ForeignKey(ProfileCollection, models.SET_NULL, blank=True, null=True)
      pass
  
  
  class Profile(models.Model):
    collection = models.ForeignKey(ProfileCollection, models.SET_NULL, blank=True, null=True)
      first_name = models.CharField(max_length=100)
      last_name = models.CharField(max_length=100)
keep keep keep keep replace keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/admin_inlines/models.py