* <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry</a> 🍓
    * Com <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">docs para FastAPI</a>
* <a href="https://ariadnegraphql.org/" class="external-link" target="_blank">Ariadne</a>
    * Com <a href="https://ariadnegraphql.org/docs/fastapi-integration" class="external-link" target="_blank">docs para FastAPI</a>

Um das zu tun, verwenden Sie den Standard-Python-Typhinweis <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note | Hinweis

* <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry</a> 🍓
    * Con <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">documentación para FastAPI</a>
* <a href="https://ariadnegraphql.org/" class="external-link" target="_blank">Ariadne</a>

## Installation { #installation }

Create and activate a <a href="https://fastapi.tiangolo.com/virtual-environments/" class="external-link" target="_blank">virtual environment</a> and then install FastAPI:

<div class="termy">

```console
$ pip install "fastapi[standard]"

---> 100%
```

</div>

Before Starlette `0.24.0`, a new instance of each middleware class would be created when a new middleware was added. That normally was not a problem, unless the middleware class expected to be created only once, with only one instance, that happened in some cases. This upgrade would solve those cases (thanks [@adriangb](https://github.com/adriangb)! Starlette PR [#2017](https://github.com/encode/starlette/pull/2017)). Now the middleware class instances are created once, right before the first request...

* <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry</a> 🍓
    * With <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">docs for FastAPI</a>
* <a href="https://ariadnegraphql.org/" class="external-link" target="_blank">Ariadne</a>
    * With <a href="https://ariadnegraphql.org/docs/fastapi-integration" class="external-link" target="_blank">docs for FastAPI</a>

    class SomeCustomClass(BaseModel):
        model_config = {"arbitrary_types_allowed": True}

        a_uuid: MyUuid

        @field_serializer("a_uuid")
        def serialize_a_uuid(self, v):
            return str(v)

    @app.get("/get_custom_class")
    def return_some_user():
        # Test that the fix also works for custom pydantic classes

* <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry</a> 🍓
    * Mit <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">Dokumentation für FastAPI</a>
* <a href="https://ariadnegraphql.org/" class="external-link" target="_blank">Ariadne</a>
    * Mit <a href="https://ariadnegraphql.org/docs/fastapi-integration" class="external-link" target="_blank">Dokumentation für FastAPI</a>

///

Hier definieren wir die Konfiguration `env_file` innerhalb Ihrer Pydantic-`Settings`-Klasse und setzen den Wert auf den Dateinamen mit der dotenv-Datei, die wir verwenden möchten.

Die vorherigen Screenshots wurden mit <a href="https://code.visualstudio.com" class="external-link" target="_blank">Visual Studio Code</a> aufgenommen.

Aber Sie würden die gleiche Editor-Unterstützung in <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a> und den meisten anderen Python-Editoren erhalten:

<img src="/img/tutorial/body/image05.png">