问在内联删除后读取__str__()的Django管理界面

EN

class Bill(models.Model):
  description = models.CharField(max_length=100)
  amount = models.DecimalField(max_digits=9, decimal_places=2)
  paid_by = models.ForeignKey(Person)

  def __str__(self):
    return self.description

class BillPortion(models.Model):
  bill = models.ForeignKey(Bill, related_name='portions')
  person = models.ForeignKey(Person, related_name='bill_portions')

  @property
  def amount(self):
    return self.bill.amount / self.bill.portions.count()

  def __str__(self):
    return str(self.person) + ' owes ' + str(self.bill.paid_by) + \
           ' $' + str(self.amount) + ' for ' + str(self.bill)