!!! info
    You can read more about the Starlette `lifespan` handlers in <a href="https://www.starlette.io/lifespan/" class="external-link" target="_blank">Starlette's  Lifespan' docs</a>.

=== "Pydantic v1"

    ```Python hl_lines="9-10"
    {!> ../../../docs_src/settings/app03_an/config_pv1.py!}
    ```

    !!! tip
        The `Config` class is used just for Pydantic configuration. You can read more at <a href="https://docs.pydantic.dev/1.10/usage/model_config/" class="external-link" target="_blank">Pydantic Model Config</a>.

    If you have an older version, you would get errors when trying to use `Annotated`.

    Make sure you [Upgrade the FastAPI version](../deployment/versions.md#upgrading-the-fastapi-versions){.internal-link target=_blank} to at least 0.95.1 before using `Annotated`.

## Declare metadata

You can declare all the same parameters as for `Query`.

    * <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

    would be valid to use as a **FastAPI** dependency.

    In fact, FastAPI uses those two decorators internally.

## Review all the files

 Remember you should have a directory named `my_super_project` that contains a sub-directory called `sql_app`.

`sql_app` should have the following files:

from typing_extensions import Annotated, Doc, ParamSpec

P = ParamSpec("P")


class BackgroundTasks(StarletteBackgroundTasks):
    """
    A collection of background tasks that will be called after a response has been
    sent to the client.

    Read more about it in the
    [FastAPI docs for Background Tasks](https://fastapi.tiangolo.com/tutorial/background-tasks/).

    ## Example

    ```python

## OpenAPI Extra

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

!!! note "Technical details"

```

### About `__name__ == "__main__"`

The main purpose of the `__name__ == "__main__"` is to have some code that is executed when your file is called with:

<div class="termy">

```console
$ python myapp.py
```

</div>

but is not called when another file imports it, like in:

```Python
from myapp import app
```

#### More details

Let's say your file is named `myapp.py`.

# Body - Updates

## Update replacing with `PUT`

To update an item you can use the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT" class="external-link" target="_blank">HTTP `PUT`</a> operation.

You can use the `jsonable_encoder` to convert the input data to data that can be stored as JSON (e.g. with a NoSQL database). For example, converting `datetime` to `str`.

=== "Python 3.10+"

    ```Python hl_lines="28-33"

    * `bearer`: a header `Authorization` with a value of `Bearer ` plus a token. This is inherited from OAuth2.
    * HTTP Basic authentication.
    * HTTP Digest, etc.
* `oauth2`: all the OAuth2 ways to handle security (called "flows").
    * Several of these flows are appropriate for building an OAuth 2.0 authentication provider (like Google, Facebook, Twitter, GitHub, etc):
        * `implicit`
        * `clientCredentials`