* Datenvalidierung
* Automatische Dokumentation

## Defaultwerte

Da Query-Parameter nicht ein festgelegter Teil des Pfades sind, können sie optional sein und Defaultwerte haben.

Im obigen Beispiel haben sie die Defaultwerte `skip=0` und `limit=10`.

Wenn Sie also zur URL:

```
http://127.0.0.1:8000/items/
```

          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,

**In our tests we also found ext4 does not honor POSIX O_DIRECT/Fdatasync semantics, ext4 trades performance for consistency guarantees. Please avoid ext4 in your setup.**

In this case, it requires the scope `me` (it could require more than one scope).

!!! note
    You don't necessarily need to add different scopes in different places.

    We are doing it here to demonstrate how **FastAPI** handles scopes declared at different levels.

=== "Python 3.10+"

    ```Python hl_lines="4  139  170"

          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,

    * Porque las estructuras de datos de Pydantic son solo <abbr title='En español: ejemplares. Aunque a veces los llaman incorrectamente "instancias"'>instances</abbr> de clases que tu defines, el auto-completado, el linting, mypy y tu intuición deberían funcionar bien con tus datos validados.
* Valida **estructuras complejas**:

## Kontextmanager

### Was sind „Kontextmanager“

„Kontextmanager“ (Englisch „Context Manager“) sind bestimmte Python-Objekte, die Sie in einer `with`-Anweisung verwenden können.

> You have to clean a big, dirty house.

*Yep, that's the whole story*.

---

There's no waiting 🕙 anywhere, just a lot of work to be done, on multiple places of the house.

You could have turns as in the burgers example, first the living room, then the kitchen, but as you are not waiting 🕙 for anything, just cleaning and cleaning, the turns wouldn't affect anything.

But Python 3.7 and above provide a more advanced alternative to `threading.local`, that can also be used in the places where `threading.local` would be used, but is compatible with the new async features.

**Spoiler alert**: the tutorial - user guide includes:

* Declaration of **parameters** from other different places as: **headers**, **cookies**, **form fields** and **files**.
* How to set **validation constraints** as `maximum_length` or `regex`.