FastAPI converts the configurations to **JSON** to make them compatible with JavaScript, as that's what Swagger UI needs.

## Disable Syntax Highlighting { #disable-syntax-highlighting }

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">

#### List { #list }

For example, let's define a variable to be a `list` of `str`.

//// tab | Python 3.9+

Declare the variable, with the same colon (`:`) syntax.

As the type, put `list`.

```Python
my_list: list[str]
```

In versions of Python before 3.9, it would be:

```Python
from typing import List

my_list: List[str]
```

That's all standard Python syntax for type declarations.

Use that same standard syntax for model attributes with internal types.

So, in our example, we can make `tags` be specifically a "list of strings":

{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

# Concurrency and async / await { #concurrency-and-async-await }

Details about the `async def` syntax for *path operation functions* and some background about asynchronous code, concurrency, and parallelism.

## In a hurry? { #in-a-hurry }

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

      - uses: actions/checkout@v5

      - name: GitHub CODEOWNERS Validator
        uses: mszostok/codeowners-validator@v0.7.4
        with:
          checks: "files,duppatterns,syntax"
          experimental_checks: "notowned,avoid-shadowing"

      # downgrading to 0.7.2 for owners check to avoid issues with token permissions check,
      # see https://github.com/mszostok/codeowners-validator/issues/224

## 6. Implementation Status

- Full AWS S3 [SELECT SQL](https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-glacier-select-sql-reference-select.html) syntax is supported.
- All [operators](https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-glacier-select-sql-reference-operators.html) are supported.
- All aggregation, conditional, type-conversion and string functions are supported.

- Initiate an id_token request to the WSO2 Identity Server, over a known [grant type](https://docs.wso2.com/display/IS540/OAuth+2.0+Grant+Types). For example, the following cURL command illustrates the syntax of an id_token request that can be initiated over the [Client Credentials Grant](https://docs.wso2.com/display/IS540/Client+Credentials+Grant) grant type.

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Just Modern Python { #just-modern-python }

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI), check the short tutorial: [Python Types](python-types.md){.internal-link target=_blank}.

# Path Parameters { #path-parameters }

You can declare path "parameters" or "variables" with the same syntax used by Python format strings:

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

The value of the path parameter `item_id` will be passed to your function as the argument `item_id`.

* declare the `q` query parameter without a `Query` nor any default value
* declare the path parameter `item_id` using `Path`
* have them in a different order
* not use `Annotated`

...Python has a little special syntax for that.

Pass `*`, as the first parameter of the function.