### Confira a documentação

Agora você pode iniciar a sua aplicação e ir até <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

Você verá que a sua documentação possui as *operações de rota* normais e agora também possui alguns **webhooks**:

    * Пайтонівський `datetime.timedelta`.
    * У запитах та відповідях буде представлений як `float` загальної кількості секунд.
    * Pydantic також дозволяє представляти це як "ISO 8601 time diff encoding", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">більше інформації дивись у документації</a>.
* `frozenset`:
    * У запитах і відповідях це буде оброблено так само, як і `set`:

    * В запросах и ответах будет представлен в виде общего количества секунд типа `float`.
    * Pydantic также позволяет представить его как "Кодировку разницы во времени ISO 8601", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">см. документацию для получения дополнительной информации</a>.
* `frozenset`:
    * В запросах и ответах обрабатывается так же, как и `set`:

Pydantic, which is what powers all the data validation and serialization in FastAPI, has a special behavior when you use `Optional` or `Union[Something, None]` without a default value, you can read more about it in the Pydantic docs about <a href="https://docs.pydantic.dev/2.3/usage/models/#required-optional-fields" class="external-link" target="_blank">Required fields</a>.

///

/// tip

///

## Check the automatic API docs

Now, run your app:

<div class="termy">

```console
$ fastapi dev app/main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

And open the docs at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

So, the line:

```Python
    uvicorn.run(app, host="0.0.0.0", port=8000)
```

will not be executed.

/// info

For more information, check <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">the official Python docs</a>.

///

## Run your code with your debugger

`@lru_cache` is part of `functools` which is part of Python's standard library, you can read more about it in the <a href="https://docs.python.org/3/library/functools.html#functools.lru_cache" class="external-link" target="_blank">Python docs for `@lru_cache`</a>.

## Recap

You can use Pydantic Settings to handle the settings or configurations for your application, with all the power of Pydantic models.

from fastapi import FastAPI
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/pydantic", response_class=RedirectResponse, status_code=302)
async def redirect_pydantic():

```

////

Notice that the *path operations* define the models they use for request payload and response payload, using the models `Item` and `ResponseMessage`.

### API Docs

If you go to the API docs, you will see that it has the **schemas** for the data to be sent in requests and received in responses:

<img src="/img/tutorial/generate-clients/image01.png">

# 📣 📨 🖼 💽

👆 💪 📣 🖼 💽 👆 📱 💪 📨.

📥 📚 🌌 ⚫️.

## Pydantic `schema_extra`

👆 💪 📣 `example` Pydantic 🏷 ⚙️ `Config` &amp; `schema_extra`, 🔬 <a href="https://docs.pydantic.dev/latest/concepts/json_schema/#customizing-json-schema" class="external-link" target="_blank">Pydantic 🩺: 🔗 🛃</a>:

//// tab | 🐍 3️⃣.6️⃣ &amp; 🔛

```Python hl_lines="15-23"
{!> ../../docs_src/schema_extra_example/tutorial001.py!}
```

////