如何在Django admin中为字段添加填充？

from django.db import models

class FilledQuerySet(models.QuerySet):
    def get_queryset(self):
        queryset = super().get_queryset()
        return queryset.annotate(field_fill=models.Value('填充值'))

class FilledManager(models.Manager):
    def get_queryset(self):
        return FilledQuerySet(self.model, using=self._db)

class YourModel(models.Model):
    field = models.CharField(max_length=100)

    objects = FilledManager()

class FilledQuerySet(models.QuerySet):
    def get_queryset(self):
        queryset = super().get_queryset()
        return queryset.annotate(
            field1_fill=models.Value('填充值1'),
            field2_fill=models.Value('填充值2')
        )

class YourModel(models.Model):
    field1 = models.CharField(max_length=100)
    field2 = models.CharField(max_length=100)

    objects = FilledManager()