      A simple, generic account encapsulating the information shared by all
      types of accounts.
      """
      username = models.CharField(blank=False, max_length=80)
      persona = models.ForeignKey(Persona, related_name="accounts")
      servicename = 'generic service'
  
      def __str__(self):
          return "%s: %s" % (self.servicename, self.username)
  
 
</s> remove         restaurant = models.ForeignKey(Restaurant)
 </s> add         restaurant = models.ForeignKey(Restaurant, on_delete=models.CASCADE) </s> remove     company = models.ForeignKey(Company, help_text="place of work")
    family = models.ForeignKey(Family, related_name='+', null=True)
 </s> add     company = models.ForeignKey(Company, models.CASCADE, help_text="place of work")
    family = models.ForeignKey(Family, models.SET_NULL, related_name='+', null=True) </s> remove     owner = models.ForeignKey(User)
 </s> add     owner = models.ForeignKey(User, models.CASCADE) </s> remove     leader = models.ForeignKey(Actor)
 </s> add     leader = models.ForeignKey(Actor, models.CASCADE) </s> remove     supervillain = models.ForeignKey(SuperVillain)
 </s> add     supervillain = models.ForeignKey(SuperVillain, models.CASCADE)
    persona = models.ForeignKey(Persona, models.CASCADE, related_name="accounts")
      A simple, generic account encapsulating the information shared by all
      types of accounts.
      """
      username = models.CharField(blank=False, max_length=80)
    persona = models.ForeignKey(Persona, models.CASCADE, related_name="accounts")
      servicename = 'generic service'
  
      def __str__(self):
          return "%s: %s" % (self.servicename, self.username)
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/admin_views/models.py