* `swagger_js_url`: the URL where the HTML for your Swagger UI docs can get the **JavaScript** file. **This is the one that your own app is now serving**.
* `swagger_css_url`: the URL where the HTML for your Swagger UI docs can get the **CSS** file. **This is the one that your own app is now serving**.

And similarly for ReDoc...

{* ../../docs_src/custom_docs_ui/tutorial002_py39.py hl[2:6,14:22,25:27,30:36] *}

from typing import Optional, Union

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class OtherItem(BaseModel):
    price: int


@app.post("/items/")
def save_union_body(item: Union[OtherItem, Item]):
    return {"item": item}


client = TestClient(app)

Esto significa que si quieres actualizar el ítem `bar` usando `PUT` con un body que contenga:

```Python
{
    "name": "Barz",
    "price": 3,
    "description": None,
}
```

debido a que no incluye el atributo ya almacenado `"tax": 20.2`, el modelo de entrada tomaría el valor por defecto de `"tax": 10.5`.

Y los datos se guardarían con ese "nuevo" `tax` de `10.5`.

    }


def test_get_item_does_not_exist(client: TestClient):
    response = client.get("/items?id=isbn-nope")
    assert response.status_code == 200, response.text
    assert response.json() == {"id": "isbn-nope", "name": None}


def test_get_invalid_item(client: TestClient):
    response = client.get("/items?id=wtf-yes")
    assert response.status_code == 422, response.text
    assert response.json() == snapshot(
        {

## レスポンスモデルのエンコーディングパラメータ

レスポンスモデルにはデフォルト値を設定することができます:

{* ../../docs_src/response_model/tutorial004.py hl[11,13,14] *}

* `description: str = None`は`None`がデフォルト値です。
* `tax: float = 10.5`は`10.5`がデフォルト値です。
* `tags: List[str] = []` は空のリスト（`[]`）がデフォルト値です。

しかし、実際に保存されていない場合には結果からそれらを省略した方が良いかもしれません。

```Python
print(user_dict)
```

obtendremos un `dict` de Python con:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': '******@****.***',
    'full_name': None,
}
```

#### Desempaquetando un `dict` { #unpacking-a-dict }

#### `Optional`

`Optional` bir değişkenin `str`gibi bir tipi olabileceğini ama isteğe bağlı olarak tipinin `None` olabileceğini belirtir:

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

`str` yerine `Optional[str]` kullanmak editorün bu değerin her zaman `str` tipinde değil bazen `None` tipinde de olabileceğini belirtir ve hataları tespit etmemizde yardımcı olur.

#### Generic tipler

     */
    void setRepository(ArtifactRepository remoteRepository);

    /**
     * Get the repository metadata associated with this marker.
     *
     * @return the metadata, or <code>null</code> if none loaded
     */
    Metadata getMetadata();

    /**
     * Set the metadata contents.
     *
     * @param metadata the metadata
     */
    void setMetadata(Metadata metadata);

    /**

     * @param key The key to use for lookup of the data, must not be {@code null}.
     * @return The requested data or {@code null} if none was present in the cache.
     */
    Object get(RepositoryRequest request, Object key);

    _os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "1"):
  import tensorflow_io_gcs_filesystem as _tensorflow_io_gcs_filesystem

# Lazy-load Keras v1.
_tf_uses_legacy_keras = (
    _os.environ.get("TF_USE_LEGACY_KERAS", None) in ("true", "True", "1"))
setattr(_current_module, "keras", _KerasLazyLoader(globals(), mode="v1"))
_module_dir = _module_util.get_parent_dir_for_name("keras._tf_keras.keras")