But at some point, there was no other option than creating something that provided all these features, taking the best ideas from previous tools, and combining them in the best way possible, using language features that weren't even available before (Python 3.6+ type hints).

## Previous tools

### <a href="https://www.djangoproject.com/" class="external-link" target="_blank">Django</a>

la valeur par défaut de `q` sera : `["foo", "bar"]`

et la réponse sera :

```JSON
{
  "q": [
    "foo",
    "bar"
  ]
}
```

#### Utiliser `list`

Il est aussi possible d'utiliser directement `list` plutôt que `List[str]` :

```Python hl_lines="7"
{!../../../docs_src/query_params_str_validations/tutorial013.py!}
```

!!! note

This schema definition includes your API paths, the possible parameters they take, etc.

#### Data "schema"

The term "schema" might also refer to the shape of some data, like a JSON content.

In that case, it would mean the JSON attributes, and data types they have, etc.

* Do not change the paths in links to images, code files, Markdown documents.

* However, when a Markdown document is translated, the `#hash-parts` in links to its headings may change. Update these links if possible.
    * Search for such links in the translated document using the regex `#[^# ]`.

=== "Python 3.10+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="6  47  54-55  58-59  68-74"
    {!> ../../../docs_src/security/tutorial004_py310.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="7  48  55-56  59-60  69-75"

In the end, the ultimate objective is to be able to **serve your API clients** in a way that is **secure**, to **avoid disruptions**, and to use the **compute resources** (for example remote servers/virtual machines) as efficiently as possible. 🚀

In Python 3.6 and above (including Python 3.10) you can use the `Union` type from `typing` and put inside the square brackets the possible types to accept.

In Python 3.10 there's also a **new syntax** where you can put the possible types separated by a <abbr title='also called "bitwise or operator", but that meaning is not relevant here'>vertical bar (`|`)</abbr>.

=== "Python 3.10+"

    {!> ../../../docs_src/bigger_applications/app_an/dependencies.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="1  4-6" title="app/dependencies.py"
    {!> ../../../docs_src/bigger_applications/app/dependencies.py!}
    ```

!!! tip
    We are using an invented header to simplify this example.

=== "Python 3.10+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="7"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_py310.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="10"

=== "Python 3.10+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="7  15"
    {!> ../../../docs_src/request_files/tutorial001_02_py310.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="9  17"
    {!> ../../../docs_src/request_files/tutorial001_02.py!}