编写带有类型标注的标准 Python：

```Python
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str
# and get editor support inside the function
def main(user_id: str):
    return user_id


# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

可以像这样来使用：

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

    @Test
    public void testSubstitution() throws IOException {
        String str = "port = 4141" + LINE_SEPARATOR + "host = localhost"
                + LINE_SEPARATOR + "url = https://${host}:${port}/service"
                + LINE_SEPARATOR;
        MavenProperties properties = new MavenProperties();
        properties.load(new StringReader(str));
        properties.put("url", "https://localhost:4141/service");

### `UploadFile`

`UploadFile` 的属性如下：

* `filename`：上传文件名字符串（`str`），例如， `myimage.jpg`；
* `content_type`：内容类型（MIME 类型 / 媒体类型）字符串（`str`），例如，`image/jpeg`；

### `UploadFile`

`UploadFile` 은 다음과 같은 어트리뷰트가 있습니다:

* `filename` : 문자열(`str`)로 된 업로드된 파일의 파일명입니다 (예: `myimage.jpg`).
* `content_type` : 문자열(`str`)로 된 파일 형식(MIME type / media type)입니다 (예: `image/jpeg`).

As, by default, singular values are interpreted as query parameters, you don't have to explicitly add a `Query`, you can just do:

```Python
q: Union[str, None] = None
```

Or in Python 3.10 and above:

```Python
q: str | None = None
```

For example:

//// tab | Python 3.10+

```Python hl_lines="28"
{!> ../../docs_src/body_multiple_params/tutorial004_an_py310.py!}
```

Da einfache Werte standardmäßig als Query-Parameter interpretiert werden, müssen Sie `Query` nicht explizit hinzufügen, Sie können einfach schreiben:

```Python
q: Union[str, None] = None
```

Oder in Python 3.10 und darüber:

```Python
q: str | None = None
```

Zum Beispiel:

//// tab | Python 3.10+

```Python hl_lines="27"
{!> ../../docs_src/body_multiple_params/tutorial004_an_py310.py!}
```

}

func (c *Content) Scan(src interface{}) error {
	var value Content
	str, ok := src.(string)
	if !ok {
		byt, ok := src.([]byte)
		if !ok {
			return errors.New("Embedded.Scan byte assertion failed")
		}
		if err := json.Unmarshal(byt, &value); err != nil {
			return err
		}
	} else {
		if err := json.Unmarshal([]byte(str), &value); err != nil {
			return err
		}
	}

	*c = value

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

////

//// tab | Python 3.6+ без Annotated

/// tip | "Подсказка"

Предпочтительнее использовать версию с аннотацией, если это возможно.

///

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

                    buf.append(getResultDataBody(entry.getKey(), d.toString()));
                    break;
                case STRING:
                    final String str = (String) xObj.value();
                    buf.append(getResultDataBody(entry.getKey(), str.trim()));
                    break;
                case NODESET:
                    final XPathNodes nodeList = (XPathNodes) xObj.value();

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")