The foreign key cannot find the model

In my FastAPI project, I wrote the model in different files and imported through CONFIG_URL, but when I set the foreign key, it shows "No model with name 'role' registered in app' my_app'". I would like to ask what is the reason, thank you very much!

my config.json is

 {
  "connections": {
    "default": "mysql://root:123123@localhost:3306/boat"
  },
  "apps": {
    "my_app": {
      "models": [
        "database.user",
        "database.department",
        "database.role"
      ],
      "default_connection": "default"
    }
  },
  "use_tz": "False",
  "timezone": "UTC"
}

the models is

    username = fields.CharField(max_length=32)
    password = fields.CharField(max_length=255)
    department_id = fields.BigIntField()
    phone = fields.CharField(max_length=16)
    mode = fields.SmallIntField()
    login_time = fields.IntField(default=0)
    remember_token = fields.CharField(max_length=255, default="")
    role: fields.ForeignKeyRelation[Role] = fields.ForeignKeyField(
        "my_app.role", related_name="roles"
    )

    class Meta:
        table = "users"

the error is

tortoise.exceptions.ConfigurationError: No model with name 'role' registered in app 'my_app'.

Start with config.json and the model declarations in database.user, database.department, and database.role. Check how the configured app registers these models and how User's ForeignKeyField refers to Role. Done means the role model is registered under my_app and the configuration error no longer occurs.