如何确保我的Django单例模型在启动时存在？

from django.db import models

class SingletonModel(models.Model):
    # 模型字段定义
    # ...

    class Meta:
        # 设置模型为抽象模型，不会生成对应的数据库表
        abstract = True

from django.apps import AppConfig
from django.db.models.signals import post_migrate
from django.dispatch import receiver

class MyAppConfig(AppConfig):
    name = 'myapp'

    def ready(self):
        # 注册信号处理函数
        post_migrate.connect(create_singleton_model, sender=self)

@receiver(post_migrate)
def create_singleton_model(sender, **kwargs):
    from myapp.models import SingletonModel

    # 检查单例模型是否已存在
    if not SingletonModel.objects.exists():
        # 创建单例模型实例
        SingletonModel.objects.create()

default_app_config = 'myapp.apps.MyAppConfig'