  
  
  @python_2_unicode_compatible
  class Album(models.Model):
      band = models.ForeignKey(Band)
      name = models.CharField(max_length=100)
      cover_art = models.FileField(upload_to='albums')
      backside_art = MyFileField(upload_to='albums_back', null=True)
  
      def __str__(self):
 
</s> remove     band = models.ForeignKey(Band)
 </s> add     band = models.ForeignKey(Band, models.CASCADE) </s> remove     team = models.ForeignKey(Team, null=True)
 </s> add     team = models.ForeignKey(Team, models.SET_NULL, null=True) </s> remove     reporter = models.ForeignKey(Reporter, null=True)
 </s> add     reporter = models.ForeignKey(Reporter, models.SET_NULL, null=True) </s> remove         artist = models.ForeignKey(Musician)
 </s> add         artist = models.ForeignKey(Musician, on_delete=models.CASCADE) </s> remove             band = UnsavedForeignKey(Band)
 </s> add             band = UnsavedForeignKey(Band, models.CASCADE)
    band = models.ForeignKey(Band, models.CASCADE)
  
  
  @python_2_unicode_compatible
  class Album(models.Model):
    band = models.ForeignKey(Band, models.CASCADE)
      name = models.CharField(max_length=100)
      cover_art = models.FileField(upload_to='albums')
      backside_art = MyFileField(upload_to='albums_back', null=True)
  
      def __str__(self):
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/admin_widgets/models.py