final Date date = toDate(str, locale);
        if (date != null) {
            return new Time(date.getTime());
        }
        final Time time = toSqlTimeJdbcEscape(str);
        if (time != null) {
            return time;
        }
        throw new ParseRuntimeException(str);
    }

    /**
     * Converts a string to a {@link Date}.
     *
     * @param str

            return new Date(((Calendar) src).getTimeInMillis());
        }
        final String str = src.toString();
        if (isEmpty(str)) {
            return null;
        }
        if (isNotEmpty(pattern)) {
            final SimpleDateFormat format = new SimpleDateFormat(pattern, locale);
            final Date date = toDate(str, format);
            if (date != null) {
                return date;
            }

    name: str | None = None
    call: Callable[..., Any] | None = None
    request_param_name: str | None = None
    websocket_param_name: str | None = None
    http_connection_param_name: str | None = None
    response_param_name: str | None = None
    background_tasks_param_name: str | None = None
    security_scopes_param_name: str | None = None
    own_oauth_scopes: list[str] | None = None

    return values


async def request_body_to_args(
    body_fields: list[ModelField],
    received_body: dict[str, Any] | FormData | bytes | None,
    embed_body_fields: bool,
) -> tuple[dict[str, Any], list[dict[str, Any]]]:
    values: dict[str, Any] = {}
    errors: list[dict[str, Any]] = []
    assert body_fields, "request_body_to_args() should be called with fields"

    serves mainly as a marker and sets the correct `Content-Type`.
    """

    media_type = "text/event-stream"


def _check_id_no_null(v: str | None) -> str | None:
    if v is not None and "\0" in v:
        raise ValueError("SSE 'id' must not contain null characters")
    return v


class ServerSentEvent(BaseModel):
    """Represents a single Server-Sent Event.

      }
      String str = builder.toString();
      HashCode hashUtf8 = murmur3_32().hashBytes(str.getBytes(UTF_8));
      assertEquals(hashUtf8, murmur3_32().newHasher().putBytes(str.getBytes(UTF_8)).hash());
      assertEquals(hashUtf8, murmur3_32().hashString(str, UTF_8));
      assertEquals(hashUtf8, murmur3_32().newHasher().putString(str, UTF_8).hash());

| 参数 | 类型 | 描述 |
|------------|------|-------------|
| `title` | `str` | API 的标题。 |
| `summary` | `str` | API 的简短摘要。 <small>自 OpenAPI 3.1.0、FastAPI 0.99.0 起可用。</small> |
| `description` | `str` | API 的简短描述。可以使用 Markdown。 |
| `version` | `string` | API 的版本。这是您自己的应用程序的版本，而不是 OpenAPI 的版本。例如 `2.5.0`。 |
| `terms_of_service` | `str` | API 服务条款的 URL。如果提供，则必须是 URL。 |

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


class User(BaseModel):
    username: str
    full_name: str | None = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: Annotated[int, Body(gt=0)],
    q: str | None = None,
):

from fastapi import FastAPI
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str | None = None
    description: str | None = None
    price: float | None = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},

```

This means that `item` could be an `int` or a `str`.

#### Possibly `None` { #possibly-none }

You can declare that a value could have a type, like `str`, but that it could also be `None`.

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////