Aber eine Variable wie `user-agent` ist in Python nicht gültig.

Darum wird `Header` standardmäßig in Parameternamen den Unterstrich (`_`) zu einem Bindestrich (`-`) konvertieren.

HTTP-Header sind außerdem unabhängig von Groß-/Kleinschreibung, darum können Sie sie mittels der Standard-Python-Schreibweise deklarieren (auch bekannt als "snake_case").

Así que, si creamos un objeto Pydantic `user_in` como:

```Python
user_in = UserIn(username="john", password="secret", email="******@****.***")
```

y luego llamamos a:

```Python
user_dict = user_in.dict()
```

ahora tenemos un `dict` con los datos en la variable `user_dict` (es un `dict` en lugar de un objeto modelo Pydantic).

Y si llamamos a:

```Python
print(user_dict)
```

      - uses: actions/checkout@v5
      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.10"
      - name: Install build dependencies
        run: pip install build
      - name: Build source distribution
        env:
          TIANGOLO_BUILD_PACKAGE: ${{ matrix.package }}
        run: python -m build --sdist
      - name: Decompress source distribution
        run: |

## Managing hermetic Python

To make sure that TensorFlow's build is reproducible, behaves uniformly across
supported platforms (Linux, Windows, MacOS) and is properly isolated from
specifics of a local system, we rely on hermetic Python (see
[rules_python](https://github.com/bazelbuild/rules_python)) for all build
and test commands executed via Bazel. This means that your system Python
installation will be ignored during the build and Python interpreter itself

<div class="termy">

```console
$ which python

/home/user/code/awesome-project/.venv/bin/python
```

</div>

Nếu nó hiển thị `python` binary tại `.venv/bin/python`, trong dự án của bạn (trong trường hợp `awesome-project`), thì tức là nó hoạt động. 🎉

////

//// tab | Windows PowerShell

<div class="termy">

```console
$ Get-Command python

* `Annotated` von `typing` (oder von `typing_extensions` in Python unter 3.9)

//// tab | Python 3.10+

In Python 3.9 oder darüber, ist `Annotated` Teil der Standardbibliothek, also können Sie es von `typing` importieren.

```Python hl_lines="1  3"
{!> ../../docs_src/query_params_str_validations/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.8+

In Versionen unter Python 3.9 importieren Sie `Annotated` von `typing_extensions`.

C:\Users\user\code\awesome-project\.venv\Scripts
```

そのため、ターミナルで `python` と入力した際に、OSはPythonプログラムを以下のパスで発見し、使用します。

```plaintext
C:\Users\user\code\awesome-project\.venv\Scripts\python
```

////

重要な点は、仮想環境のパスを `PATH` 変数の**先頭**に配置することです。OSは利用可能な他のPythonを見つけるより**前に**、この仮想環境のPythonを見つけるようになります。このようにして、 `python` を実行したときに、他の `python` （例えばグローバル環境の `python` ）ではなく、**その仮想環境の**Pythonを使用するようになります。

仮想環境を有効にして変更されることは他にもありますが、これが最も重要な変更のひとつです。

### Just Modern Python { #just-modern-python }

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI), check the short tutorial: [Python Types](python-types.md){.internal-link target=_blank}.

You write standard Python with types:

```Python

-   type: dropdown id: source attributes: label: Source description: Tensorflow

Ahora utilizaremos una dependencia simple para leer un encabezado `X-Token` personalizado:

//// tab | Python 3.9+

```Python hl_lines="3  6-8" title="app/dependencies.py"
{!> ../../docs_src/bigger_applications/app_an_py39/dependencies.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="1  5-7" title="app/dependencies.py"
{!> ../../docs_src/bigger_applications/app_an/dependencies.py!}
```