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That command line program called `fastapi` is **FastAPI CLI**.

FastAPI CLI takes the path to your Python program and automatically detects the variable with the FastAPI (commonly named `app`) and how to import it, and then serves it.

For production you would use `fastapi run` instead. 🚀

And these models are all sharing a lot of the data and duplicating attribute names and types.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

All the data conversion, validation, documentation, etc. will still work as normally.

    ```

As in this case (without using `Annotated`) we have to replace the default value `None` in the function with `Query()`, we now need to set the default value with the parameter `Query(default=None)`, it serves the same purpose of defining that default value (at least for FastAPI).

So:

```Python
q: Union[str, None] = Query(default=None)
```

Used by FastAPI / Starlette:

* <a href="https://www.uvicorn.org" target="_blank"><code>uvicorn</code></a> - for the server that loads and serves your application.
* <a href="https://github.com/ijl/orjson" target="_blank"><code>orjson</code></a> - Required if you want to use `ORJSONResponse`.

    FastAPI kann sie in jedem Fall überschreiben.

Anschließend können Sie Ihre Überschreibungen zurücksetzen (entfernen), indem Sie `app.dependency_overrides` auf ein leeres `dict` setzen:

```Python
app.dependency_overrides = {}
```

!!! tip "Tipp"

Used by FastAPI / Starlette:

* <a href="https://www.uvicorn.org" target="_blank"><code>uvicorn</code></a> - for the server that loads and serves your application.
* <a href="https://github.com/ijl/orjson" target="_blank"><code>orjson</code></a> - Required if you want to use `ORJSONResponse`.

Contêineres Linux rodam usando o mesmo kernel Linux do hospedeiro (máquina, máquina virtual, servidor na nuvem, etc). Isso simplesmente significa que eles são muito leves (comparados com máquinas virtuais emulando um sistema operacional completo).

Dessa forma, contêineres consomem **poucos recursos**, uma quantidade comparável com rodar os processos diretamente (uma máquina virtual consumiria muito mais).