client = TestClient(app)


def test_swagger_ui():
    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert (
        '"syntaxHighlight": false' in response.text
    ), "syntaxHighlight should be included and converted to JSON"
    assert (
        '"dom_id": "#swagger-ui"' in response.text
    ), "default configs should be preserved"

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:

<img src="/img/tutorial/extending-openapi/image03.png">

## Change the Theme

The same way you could set the syntax highlighting theme with the key `"syntaxHighlight.theme"` (notice that it has a dot in the middle):

def test_swagger_ui():
    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert (
        '"syntaxHighlight": false' not in response.text
    ), "not used parameters should not be included"
    assert (
        '"syntaxHighlight.theme": "obsidian"' in response.text
    ), "parameters with middle dots should be included in a JSON compatible way"
    assert (

from fastapi import FastAPI

app = FastAPI(swagger_ui_parameters={"syntaxHighlight.theme": "obsidian"})


@app.get("/users/{username}")
async def read_user(username: str):

Ohne Änderung der Einstellungen ist die Syntaxhervorhebung standardmäßig aktiviert:

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

Sie können sie jedoch deaktivieren, indem Sie `syntaxHighlight` auf `False` setzen:

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

... und dann zeigt die Swagger-Oberfläche die Syntaxhervorhebung nicht mehr an:

from fastapi import FastAPI

app = FastAPI(swagger_ui_parameters={"syntaxHighlight": False})


@app.get("/users/{username}")
async def read_user(username: str):

    ), "overridden configs should be preserved"
    assert (
        '"deepLinking": true' not in response.text
    ), "overridden configs should not include the old value"
    assert (
        '"syntaxHighlight": false' not in response.text
    ), "not used parameters should not be included"
    assert (
        '"dom_id": "#swagger-ui"' in response.text
    ), "default configs should be preserved"