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

### Düzenle

Bu çok basit bir program.

Ama şimdi sıfırdan yazdığınızı hayal edin.

Bir noktada fonksiyonun tanımına başlayacaktınız, parametreleri hazır hale getirdiniz...

Ama sonra "ilk harfi büyük harfe dönüştüren yöntemi" çağırmanız gerekir.

 `upper` mıydı ? Yoksa  `uppercase`' mi? `first_uppercase`? `capitalize`?

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" vertex="1" parent="33">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" parent="33" vertex="1">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" parent="33" vertex="1">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

                </mxCell>
                <mxCell id="32" value="" style="pointerEvents=1;shadow=0;dashed=0;html=1;fillColor=#505050;labelPosition=center;verticalLabelPosition=bottom;verticalAlign=top;outlineConnect=0;align=center;shape=mxgraph.office.devices.laptop;strokeColor=none;" parent="33" vertex="1">
                    <mxGeometry width="500" height="350" as="geometry"/>
                </mxCell>

There's a high chance that the logic for your *startup* and *shutdown* is connected, you might want to start something and then finish it, acquire a resource and then release it, etc.

Doing that in separated functions that don't share logic or variables together is more difficult as you would need to store values in global variables or similar tricks.

Because of that, it's now recommended to instead use the `lifespan` as explained above.

Sağladığı basitlik ve esneklik NoSQL veritabanlarını ana veritabanı sistemi olarak kullanmak gibi şeyler yapmaya olanak sağlar.

Yapısı oldukça basit olduğundan öğrenmesi de nispeten basittir, tabii dökümantasyonu bazı noktalarda biraz teknik hale geliyor.

* `lt`: `l`ess `t`han
* `le`: `l`ess than or `e`qual

!!! info
    `Query`, `Path`, and other classes you will see later are subclasses of a common `Param` class.

    All of them share the same parameters for additional validation and metadata you have seen.

!!! note "Technical Details"
    When you import `Query`, `Path` and others from `fastapi`, they are actually functions.

<img src="/img/python-types/image06.png">

## Pydantic 모델

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>은 데이터 검증(Validation)을 위한 파이썬 라이브러리입니다.

당신은 속성들을 포함한 클래스 형태로 "모양(shape)"을 선언할 수 있습니다.

그리고 각 속성은 타입을 가지고 있습니다.

이 클래스를 활용하여서 값을 가지고 있는 인스턴스를 만들게 되면, 필요한 경우에는 적당한 타입으로 변환까지 시키기도 하여 데이터가 포함된 객체를 반환합니다.

그리고 결과 객체에 대해서는 에디터의 도움을 받을 수 있게 됩니다.

Pydantic 공식 문서 예시:

```Python hl_lines="3  5"
{!../../../docs_src/dependencies/tutorial007.py!}
```

## Sub-dependencies with `yield`

You can have sub-dependencies and "trees" of sub-dependencies of any size and shape, and any or all of them can use `yield`.

**FastAPI** will make sure that the "exit code" in each dependency with `yield` is run in the correct order.