def post_root(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    @router.post(
        "/router", response_model=list[Item], responses={404: {"model": list[Message]}}
    )
    def post_router(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    app.include_router(router)
    client = TestClient(app)

    type: str = "car"


class PlaneItem(BaseItem):
    type: str = "plane"
    size: int


items = {
    "item1": {"description": "All my friends drive a low rider", "type": "car"},
    "item2": {
        "description": "Music is my aeroplane, it's my aeroplane",
        "type": "plane",
        "size": 5,
    },
}


@app.get("/items/{item_id}", response_model=Union[PlaneItem, CarItem])

    assert response.json() == {
        "description": "All my friends drive a low rider",
        "type": "car",
    }


def test_get_plane(client: TestClient):
    response = client.get("/items/item2")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "description": "Music is my aeroplane, it's my aeroplane",
        "type": "plane",
        "size": 5,
    }

    * This applies to ORMs like SQLAlchemy, Peewee, Tortoise ORM, GINO ORM and virtually any other.
    * If your *path operations* return an arbitrary object with attributes (e.g. `my_item.name` instead of `my_item["name"]`) AND you use a `response_model`, make sure to update the Pydantic models with `orm_mode = True` as described in the docs (link above).