  
  
  class Bug(Issue):
      version = models.CharField(max_length=50)
      reporter = models.ForeignKey(BaseUser)
  
  
  class ProxyBug(Bug):
      """
      Proxy of an inherited class
 
</s> remove     reporter = models.ForeignKey(ProxyTrackerUser)
    associated_bug = models.ForeignKey(ProxyProxyBug)
 </s> add     reporter = models.ForeignKey(ProxyTrackerUser, models.CASCADE)
    associated_bug = models.ForeignKey(ProxyProxyBug, models.CASCADE) </s> remove     reporter = models.ForeignKey(Reporter, null=True)
 </s> add     reporter = models.ForeignKey(Reporter, models.SET_NULL, null=True) </s> remove     user = models.OneToOneField(User, primary_key=True)
 </s> add     user = models.OneToOneField(User, models.CASCADE, primary_key=True) </s> remove     reporter = models.ForeignKey(Reporter)
    response_to = models.ForeignKey('self', null=True)
 </s> add     reporter = models.ForeignKey(Reporter, models.CASCADE)
    response_to = models.ForeignKey('self', models.SET_NULL, null=True) </s> remove     parent = models.ForeignKey(ParentWithDependentChildren)
 </s> add     parent = models.ForeignKey(ParentWithDependentChildren, models.CASCADE)
    reporter = models.ForeignKey(BaseUser, models.CASCADE)
  
  
  class Bug(Issue):
      version = models.CharField(max_length=50)
    reporter = models.ForeignKey(BaseUser, models.CASCADE)
  
  
  class ProxyBug(Bug):
      """
      Proxy of an inherited class
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/proxy_models/models.py