Bu durumda, bu bir `async` fonksiyondur.

---

Bunu `async def` yerine normal bir fonksiyon olarak da tanımlayabilirsiniz:

{* ../../docs_src/first_steps/tutorial003_py310.py hl[7] *}

/// note | Not

Eğer farkı bilmiyorsanız, [Async: *"Aceleniz mi var?"*](../async.md#in-a-hurry) sayfasına bakın.

///

	eventsSkipped     atomic.Int64
	eventsErrorsTotal atomic.Int64

	sync.RWMutex
	targets map[TargetID]Target
	queue   chan asyncEvent
	ctx     context.Context

	statLock    sync.RWMutex
	targetStats map[TargetID]targetStat
}

type targetStat struct {
	// The number of concurrent async Send calls per targets
	currentSendCalls int64
	// The number of total events per target
	totalEvents int64

It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[6:9] *}

//// tab | Python 3.10+

```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.10+ 비 Annotated

/// tip | 팁

가능하다면 `Annotated` 버전을 사용하는 것을 권장합니다.

///

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):

//// tab | Python 3.10+

```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.10+ 未使用 Annotated

/// tip

若可行，建議使用 `Annotated` 的版本。

///

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            openapi_examples={
                "normal": {
                    "summary": "A normal example",

```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="7  12"
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):

```

<details markdown="1">
<summary>或使用 <code>async def</code>...</summary>

如果你的程式碼使用 `async` / `await`，請使用 `async def`：

```Python hl_lines="7  12"
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):

Es solo una función estándar que puede recibir parámetros.

Puede ser una función `async def` o una función normal `def`, **FastAPI** sabrá cómo manejarla correctamente.

En este caso, la función de tarea escribirá en un archivo (simulando el envío de un email).

Y como la operación de escritura no usa `async` y `await`, definimos la función con un `def` normal:

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize",
    tokenUrl="token",
    description="OAuth2 Code Bearer",
    auto_error=True,
)


@app.get("/items/")
async def read_items(token: str | None = Security(oauth2_scheme)):
    return {"token": token}


client = TestClient(app)


def test_no_token():
    response = client.get("/items")