For example, you could disable syntax highlighting in Swagger UI.

Without changing the settings, syntax highlighting is enabled by default:

<img src="/img/tutorial/extending-openapi/image02.png">

But you can disable it by setting `syntaxHighlight` to `False`:

```Python hl_lines="3"
{!../../../docs_src/configure_swagger_ui/tutorial001.py!}
```

...and then Swagger UI won't show the syntax highlighting anymore:

from fastapi import APIRouter

router = APIRouter()


@router.post("/")
async def update_admin():

from fastapi import APIRouter

router = APIRouter()


@router.post("/")
async def update_admin():

    client = TestClient(tutorial001.app)
    return client


@needs_pydanticv2
def test_disable_openapi(monkeypatch):
    monkeypatch.setenv("OPENAPI_URL", "")
    # Load the client after setting the env var
    client = get_client()
    response = client.get("/openapi.json")
    assert response.status_code == 404, response.text
    response = client.get("/docs")
    assert response.status_code == 404, response.text

    FastAPI will still be able to override it.

Then you can reset your overrides (remove them) by setting `app.dependency_overrides` to be an empty `dict`:

```Python
app.dependency_overrides = {}
```

!!! tip

  deta [command]

Available Commands:
  auth        Change auth settings for a deta micro

...
```

</div>

!!! tip "提示"

    安装 CLI 遇到问题时，请参阅 <a href="https://docs.deta.sh/docs/micros/getting_started?ref=fastapi" class="external-link" target="_blank">Deta 官档</a>。

## 使用 CLI 登录

现在，使用 CLI 登录 Deta：

<div class="termy">

```console
$ deta login

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

    ```Python hl_lines="10"
    {!> ../../../docs_src/header_params/tutorial002.py!}
    ```

!!! warning
    Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

## Duplicate headers

This can be very useful for setting up **resources** that you need to use for the whole app, and that are **shared** among requests, and/or that you need to **clean up** afterwards. For example, a database connection pool, or loading a shared machine learning model.

The exception handler will receive a `Request` and the exception.

```Python hl_lines="2  14-16"
{!../../../docs_src/handling_errors/tutorial004.py!}
```

Now, if you go to `/items/foo`, instead of getting the default JSON error with:

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],

```

</div>

!!! tip
    To set multiple env vars for a single command just separate them with a space, and put them all before the command.

And then the `admin_email` setting would be set to `"******@****.***"`.

The `app_name` would be `"ChimichangApp"`.

And the `items_per_user` would keep its default value of `50`.

## Settings in another module