```JSON
{"item_id":3}
```

!!! check
    Notice that the value your function received (and returned) is `3`, as a Python `int`, not a string `"3"`.

    So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

## Data validation

👆 💪 🛠️ ⚫️ 🙆 🎏 ☁ 💽 💖:

* **✳**
* **👸**
* **✳**
* **🇸🇲**
* **✳**, ♒️.

!!! tip

{!../../../docs_src/nosql_databases/tutorial001.py!}
```

### f-strings

If you are not familiar with the `f"userprofile::{username}"`, it is a Python "<a href="https://docs.python.org/3/glossary.html#term-f-string" class="external-link" target="_blank">f-string</a>".

Any variable that is put inside of `{}` in an f-string will be expanded / injected in the string.

### `dict` unpacking

In diesem Fall macht es Sinn, die Tags in einem `Enum` zu speichern.

**FastAPI** unterstützt diese genauso wie einfache Strings:

```Python hl_lines="1  8-10  13  18"
{!../../../docs_src/path_operation_configuration/tutorial002b.py!}
```

## Zusammenfassung und Beschreibung

    ```

## Set types

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

=== "Python 3.10+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/body_nested_models/tutorial003_py310.py!}
    ```

=== "Python 3.9+"

Da sie Teil der URL sind, sind sie „naturgemäß“ Strings.

Aber wenn Sie sie mit Python-Typen deklarieren (im obigen Beispiel als `int`), werden sie zu diesem Typ konvertiert, und gegen diesen validiert.

Die gleichen Prozesse, die für Pfad-Parameter stattfinden, werden auch auf Query-Parameter angewendet:

* Editor Unterstützung (natürlich)

    ...
```

But right at the moment Python compares the first `j` in `johndoe` to the first `s` in `stanleyjobson`, it will return `False`, because it already knows that those two strings are not the same, thinking that "there's no need to waste more computation comparing the rest of the letters". And your application will say "Incorrect username or password".

```JSON
{"item_id":3}
```

!!! check "Revisa"
    Observa que el valor que recibió (y devolvió) tu función es `3`, como un Python `int`, y no un string `"3"`.

    Entonces, con esa declaración de tipos **FastAPI** te da <abbr title="convertir el string que viene de un HTTP request a datos de Python">"parsing"</abbr> automático del request.

## Validación de datos

```JSON
{"item_id":3}
```

!!! check "Verifique"
	Observe que o valor recebido pela função (e também retornado por ela) é `3`, como um Python `int`, não como uma string `"3"`.

	Então, com essa declaração de tipo, o **FastAPI** dá pra você um <abbr title="convertendo a string que veio do request HTTP em um dado Python">"parsing"</abbr> automático no request .

## Validação de dados

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../../docs_src/path_operation_configuration/tutorial002b.py!}
```

## Summary and description

You can add a `summary` and `description`:

=== "Python 3.10+"