//// tab | Python 3.10+

```Python hl_lines="26-27  30"
{!> ../../docs_src/dependency_testing/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="28-29  32"
{!> ../../docs_src/dependency_testing/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="29-30  33"

//// tab | Python 3.10+

```Python hl_lines="26-27  30"
{!> ../../docs_src/dependency_testing/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="28-29  32"
{!> ../../docs_src/dependency_testing/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="29-30  33"

## Импорт `Header`

Сперва импортируйте `Header`:

//// tab | Python 3.10+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an.py!}
```

## `Header` importieren

Importieren Sie zuerst `Header`:

//// tab | Python 3.10+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an.py!}
```

使用 Python `list` 可以接收重复请求头所有的值。

例如，声明 `X-Token` 多次出现的请求头，可以写成这样：

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/header_params/tutorial003_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="9"
{!> ../../docs_src/header_params/tutorial003_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="10"

//// tab | Python 3.10+

```Python hl_lines="68-69  82"
{!> ../../docs_src/websockets/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="68-69  82"
{!> ../../docs_src/websockets/tutorial002_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="69-70  83"

//// tab | Python 3.10+

```Python hl_lines="9  17"
{!> ../../docs_src/request_files/tutorial001_02_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="9  17"
{!> ../../docs_src/request_files/tutorial001_02_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="10  18"

```Python hl_lines="7"
{!../../docs_src/first_steps/tutorial001.py!}
```

Это обычная Python функция.

**FastAPI** будет вызывать её каждый раз при получении `GET` запроса к URL "`/`".

В данном случае это асинхронная функция.

---

Вы также можете определить ее как обычную функцию вместо `async def`:

```Python hl_lines="7"

```Python
{!../../docs_src/sql_databases/sql_app/models.py!}
```

* `sql_app/schemas.py`:

//// tab | Python 3.10+

```Python
{!> ../../docs_src/sql_databases/sql_app_py310/schemas.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/sql_databases/sql_app_py39/schemas.py!}
```

////

//// tab | Python 3.8+

```Python

# Yol Parametreleri

Yol "parametrelerini" veya "değişkenlerini" Python <abbr title="String Biçimleme: Format String">string biçimlemede</abbr> kullanılan sözdizimi ile tanımlayabilirsiniz.

```Python hl_lines="6-7"
{!../../docs_src/path_params/tutorial001.py!}
```

Yol parametresi olan `item_id`'nin değeri, fonksiyonunuza `item_id` argümanı olarak aktarılacaktır.