```Python
old_dict = {
    "old key": "old value",
    "second old key": "second old value",
}
new_dict = {**old_dict, "new key": "new value"}
```

Ici, `new_dict` contiendra toutes les paires clé-valeur de `old_dict` plus la nouvelle paire clé-valeur :

```Python
{
    "old key": "old value",
    "second old key": "second old value",
    "new key": "new value",
}
```

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info
    `**second_user_data` nghĩa là:

def test_get_invalid_second_header_items():
    response = client.get(
        "/items/", headers={"X-Token": "fake-super-secret-token", "X-Key": "invalid"}
    )
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Key header invalid"}


def test_get_invalid_second_header_users():
    response = client.get(

    `HTTPDigest` in a dependency.

    The HTTP authorization header value is split by the first space.

    The first part is the `scheme`, the second part is the `credentials`.

    For example, in an HTTP Bearer token scheme, the client will send a header
    like:

    ```
    Authorization: Bearer deadbeef12346
    ```

    In this case:

    * `scheme` will have the value `"Bearer"`

Cela va valider les données, montrer une erreur claire si ces dernières ne sont pas valides, et documenter le paramètre dans le schéma `OpenAPI` de cette *path operation*.

## Rajouter plus de validation

Vous pouvez aussi rajouter un second paramètre `min_length` :

```Python hl_lines="9"
{!../../../docs_src/query_params_str_validations/tutorial003.py!}
```

## Ajouter des validations par expressions régulières

Quand vous créez des *fonctions de chemins*, vous pouvez vous retrouver dans une situation où vous avez un chemin fixe.

Tel que `/users/me`, disons pour récupérer les données sur l'utilisateur actuel.

Et vous avez un second chemin : `/users/{user_id}` pour récupérer de la donnée sur un utilisateur spécifique grâce à son identifiant d'utilisateur

* **`300`** and above are for "Redirection".  Responses with these status codes may or may not have a body, except for `304`, "Not Modified", which must not have one.
* **`400`** and above are for "Client error" responses. These are the second type you would probably use the most.
    * An example is `404`, for a "Not Found" response.
    * For generic errors from the client, you can just use `400`.

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info
    `**second_user_data` means:

    Pass the keys and values of the `second_user_data` dict directly as key-value arguments, equivalent to: `User(id=4, name="Mary", joined="2018-11-30")`

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info
    `**second_user_data` quer dizer:

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info
    `**second_user_data` signifie: