class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    size: float


class ItemV2(BaseModelV2):
    name: str
    description: Union[str, None] = None
    size: float


app = FastAPI()


@app.post("/items/", response_model=ItemV2)
async def create_item(item: Item):

{* ../../docs_src/pydantic_v1_in_v2/tutorial003_an_py310.py hl[2:3,6,12,21:22] *}

Im obigen Beispiel ist das Eingabemodell ein Pydantic‑v1‑Modell, und das Ausgabemodell (definiert in `response_model=ItemV2`) ist ein Pydantic‑v2‑Modell.

### Pydantic v1 Parameter { #pydantic-v1-parameters }

{* ../../docs_src/pydantic_v1_in_v2/tutorial003_an_py310.py hl[2:3,6,12,21:22] *}

In this example above, the input model is a Pydantic v1 model, and the output model (defined in `response_model=ItemV2`) is a Pydantic v2 model.

### Pydantic v1 parameters { #pydantic-v1-parameters }

{* ../../docs_src/pydantic_v1_in_v2/tutorial003_an_py310.py hl[2:3,6,12,21:22] *}

En el ejemplo anterior, el modelo de entrada es un modelo de Pydantic v1 y el modelo de salida (definido en `response_model=ItemV2`) es un modelo de Pydantic v2.

### Parámetros de Pydantic v1 { #pydantic-v1-parameters }

    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)

    return item


def dependency(item2: Item):
    return item2


def sub_duplicate_dependency(
    item: Item, sub_item: Item = Depends(duplicate_dependency)
):
    return [item, sub_item]


@app.post("/with-duplicates")
async def with_duplicates(item: Item, item2: Item = Depends(duplicate_dependency)):
    return [item, item2]


@app.post("/no-duplicates")

        item_id: str = Path(
            examples=["item_1", "item_2"],
        ),
    ):
        return item_id

    with pytest.warns(FastAPIDeprecationWarning):

        @app.get("/path_example_examples/{item_id}")
        def path_example_examples(
            item_id: str = Path(
                example="item_overridden",
                examples=["item_1", "item_2"],
            ),
        ):

    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])

                "summary": "Path One Summary",
                "description": "Path One Description",
                "value": "item_1",
            },
            "Path Two": {
                "value": "item_2",
            },
        },
    ),
):
    return item_id


@app.get("/query_examples/")
def query_examples(
    data: Union[str, None] = Query(
        default=None,
        examples=[

    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,
    }