but you might want to omit them from the result if they were not actually stored.

For example, if you have models with many optional attributes in a NoSQL database, but you don't want to send very long JSON responses full of default values.

### Use the `response_model_exclude_unset` parameter

You can set the *path operation decorator* parameter `response_model_exclude_unset=True`:

=== "Python 3.10+"

    And after searching for a long time for a similar framework and testing many different alternatives, APIStar was the best option available.

---

Another useful case is when you want to have keys of another type (e.g., `int`).

That's what we are going to see here.

In this case, you would accept any `dict` as long as it has `int` keys with `float` values:

=== "Python 3.9+"

    ```Python hl_lines="7"
    {!> ../../../docs_src/body_nested_models/tutorial009_py39.py!}
    ```

=== "Python 3.8+"

Or you might have any other way to communicate with the WebSocket endpoint.

---

But for this example, we'll use a very simple HTML document with some JavaScript, all inside a long string.

This, of course, is not optimal and you wouldn't use it for production.

In production you would have one of the options above.

# Concurrency ve async / await

*path operasyon fonksiyonu* için `async def `sözdizimi,  asenkron kod, eşzamanlılık ve paralellik hakkında bazı ayrıntılar.

## Aceleniz mi var?

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

Eğer `await` ile çağrılması gerektiğini belirten üçüncü taraf kütüphaneleri kullanıyorsanız, örneğin:

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

# 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?

<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()
```

### `scope`

The spec also says that the client can send another form field "`scope`".

The form field name is `scope` (in singular), but it is actually a long string with "scopes" separated by spaces.

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example:

    assert response.status_code == 422
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "string_too_long",
                    "loc": ["path", "item_id"],
                    "msg": "String should have at most 3 characters",
                    "input": "foobar",
                    "ctx": {"max_length": 3},

The keys of the `dict` identify each example, and each value is another `dict`.

Each specific example `dict` in the `examples` can contain:

* `summary`: Short description for the example.
* `description`: A long description that can contain Markdown text.
* `value`: This is the actual example shown, e.g. a `dict`.

# Nebenläufigkeit und async / await

Details zur `async def`-Syntax für *Pfadoperation-Funktionen* und Hintergrundinformationen zu asynchronem Code, Nebenläufigkeit und Parallelität.

## In Eile?

<abbr title="too long; didn't read – Zu lang; nicht gelesen"><strong>TL;DR:</strong></abbr>

Wenn Sie Bibliotheken von Dritten verwenden, die mit `await` aufgerufen werden müssen, wie zum Beispiel:

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