## Eine Abhängigkeit mit `yield` und `try`.

Wenn Sie einen `try`-Block in einer Abhängigkeit mit `yield` verwenden, empfangen Sie alle Exceptions, die bei Verwendung der Abhängigkeit geworfen wurden.

Or it might be the case that you just prefer to take other courses because they adapt better to your learning style.

Some course providers ✨ [**sponsor FastAPI**](../help-fastapi.md#sponsor-the-author){.internal-link target=_blank} ✨, this ensures the continued and healthy **development** of FastAPI and its **ecosystem**.

### Is concurrency better than parallelism?

Nope! That's not the moral of the story.

Concurrency is different than parallelism. And it is better on **specific** scenarios that involve a lot of waiting. Because of that, it generally is a lot better than parallelism for web application development. But not for everything.

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  <a href="https://fastapi.tiangolo.com"><img src="https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png" alt="FastAPI"></a>
</p>
<p align="center">
    FastAPI framework, yüksek performanslı, öğrenmesi oldukça kolay, kodlaması hızlı, kullanıma hazır
</p>
<p align="center">

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    Готовий до продакшину, високопродуктивний, простий у вивченні та швидкий для написання коду фреймворк
</p>
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<a href="https://github.com/tiangolo/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

!!! check
    Beachten Sie auch, dass **FastAPI** intelligent genug ist, um zu erkennen, dass `item_id` ein Pfad-Parameter ist und `q` keiner, daher muss letzteres ein Query-Parameter sein.

## Query-Parameter Typkonvertierung

Sie können auch `bool`-Typen deklarieren und sie werden konvertiert:

=== "Python 3.10+"

    ```Python hl_lines="7"

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    Framework FastAPI, haute performance, facile à apprendre, rapide à coder, prêt pour la production
</p>
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</p>
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    FastAPI framework, high performance, easy to learn, fast to code, ready for production
</p>
<p align="center">
<a href="https://github.com/tiangolo/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">

hide:
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---

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    FastAPI 🛠️, ↕ 🎭, ⏩ 💡, ⏩ 📟, 🔜 🏭
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```json
{"message": "Hello World"}
```

...this response will return:

```json
{
  "message": "Hello World"
}
```

Of course, you will probably find much better ways to take advantage of this than formatting JSON. 😉

## Default response class

When creating a **FastAPI** class instance or an `APIRouter` you can specify which response class to use by default.