assertSame(stringIdentityConverter, stringIdentityConverter.reverse());
    assertSame(STR_TO_LONG, stringIdentityConverter.andThen(STR_TO_LONG));

    assertSame(STR_VAL, stringIdentityConverter.convert(STR_VAL));
    assertSame(STR_VAL, stringIdentityConverter.reverse().convert(STR_VAL));

    assertEquals("Converter.identity()", stringIdentityConverter.toString());

{!../../../docs_src/python_types/tutorial009.py!}
```

Использование `Optional[str]` вместо просто `str` позволит редактору помочь вам в обнаружении ошибок, в которых вы могли бы предположить, что значение всегда является `str`, хотя на самом деле это может быть и `None`.

#### Generic-типы

Эти типы принимают параметры в квадратных скобках:

* `List`
* `Tuple`
* `Set`
* `Dict`
* `Optional`
* ...и др.

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: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: str | None = None,
    item: Item | None = None,
):
    results = {"item_id": item_id}
    if q:

⚫️ ✊ 📇 ⚗ 1️⃣ 📖 🔠 🔖.

🔠 📖 💪 🔌:

* `name` (**✔**): `str` ⏮️ 🎏 📛 👆 ⚙️ `tags` 🔢 👆 *➡ 🛠️* & `APIRouter`Ⓜ.
* `description`: `str` ⏮️ 📏 📛 🔖. ⚫️ 💪 ✔️ ✍ & 🔜 🎦 🩺 🎚.
* `externalDocs`: `dict` 🔬 🔢 🧾 ⏮️:
    * `description`: `str` ⏮️ 📏 📛 🔢 🩺.
    * `url` (**✔**): `str` ⏮️ 📛 🔢 🧾.

### ✍ 🗃 🔖

➡️ 🔄 👈 🖼 ⏮️ 🔖 `users` & `items`.

    return not (current_status_code < 200 or current_status_code in {204, 205, 304})


def get_path_param_names(path: str) -> Set[str]:
    return set(re.findall("{(.*?)}", path))


def create_response_field(
    name: str,
    type_: Type[Any],
    class_validators: Optional[Dict[str, Validator]] = None,
    default: Optional[Any] = Undefined,
    required: Union[bool, UndefinedType] = Undefined,

app = FastAPI(default_response_class=ORJSONResponse)


@app.get("/orjson_non_str_keys")
def get_orjson_non_str_keys():
    key = quoted_name(value="msg", quote=False)
    return {key: "Hello World", 1: 1}


client = TestClient(app)


def test_orjson_non_str_keys():
    with client:
        response = client.get("/orjson_non_str_keys")

returnAfterGrowFromGo(void)
{
	extern int goReturnVal(void);
	return goReturnVal();
}

void
callGoWithString(void)
{
	extern void goWithString(GoString);
	const char *str = "string passed from C to Go";
	goWithString((GoString){str, strlen(str)});

from typing import Annotated

from fastapi import BackgroundTasks, Depends, FastAPI

app = FastAPI()


def write_log(message: str):
    with open("log.txt", mode="a") as log:
        log.write(message)


def get_query(background_tasks: BackgroundTasks, q: str | None = None):
    if q:
        message = f"found query: {q}\n"
        background_tasks.add_task(write_log, message)
    return q

    /**
     * ブランクかどうか返します。
     *
     * @param str
     *            文字列
     * @return ブランクなら{@literal true}
     */
    public static boolean isBlank(final String str) {
        if (str == null || str.length() == 0) {
            return true;
        }
        for (int i = 0; i < str.length(); i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return false;
            }

def test_model_field_default_required():
    # For coverage
    field_info = FieldInfo(annotation=str)
    field = ModelField(name="foo", field_info=field_info)
    assert field.default is Undefined


@needs_pydanticv1
def test_upload_file_dummy_with_info_plain_validator_function():
    # For coverage
    assert UploadFile.__get_pydantic_core_schema__(str, lambda x: None) == {}


@needs_pydanticv1
def test_union_scalar_list():