// Do not care If-Modified-Since, Because:
			// 1. If If-Modified-Since condition evaluates to true.
			//  If both of the If-None-Match and If-Modified-Since headers are present in the request as follows:
			// 	If-None-Match condition evaluates to false , and;
			//  If-Modified-Since condition evaluates to true ;
			// 	Then Amazon S3 returns the 304 Not Modified response code.

	if maxProcs < len(disks) {
		disks = disks[:maxProcs]
	}

	// Start one scanner per disk
	var wg sync.WaitGroup
	wg.Add(len(disks))

	for i := range disks {
		go func(i int) {
			defer wg.Done()
			disk := disks[i]

			for bucket := range bucketCh {
				select {
				case <-ctx.Done():
					return
				default:
				}

				// Load cache for bucket

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The Bar fighters", "price": 62, "tax": 20.2},
    "baz": {
        "name": "Baz",
        "description": "There goes my baz",

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5


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

:"false"===a&&(i.hide(),i.parent().parent().addClass("d-none"))}))},t.toggleRow=function(){var e=this._element;"TR"!==e[0].nodeName&&"TR"!==(e=e.parent())[0].nodeName&&(e=e.parent());var t=e.attr(ee),a=e.next(Y).children().first().children();a.stop(),"true"===t?(a.slideUp(500,(function(){e.next(Y).addClass("d-none")})),e.attr(ee,"false"),e.trigger(n.default.Event("collapsed.lte.expandableTable"))):"false"===t&&(e.next(Y).removeClass("d-none"),a.slideDown(500),e.attr(ee,"true"),e.trigger(n.defaul...

        raise ValueError('Invalid ID format, it must start with "isbn-" or "imdb-"')
    return id


@app.get("/items/")
async def read_items(
    id: Annotated[str | None, AfterValidator(check_valid_id)] = None,
):
    if id:
        item = data.get(id)
    else:
        id, item = random.choice(list(data.items()))

from pydantic.v1 import BaseModel


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

## 선택적 매개변수

같은 방법으로 기본값을 `None`으로 설정하여 선택적 매개변수를 선언할 수 있습니다:

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

이 경우 함수 매개변수 `q`는 선택적이며 기본값으로 `None` 값이 됩니다.

/// check | 확인

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | 참고

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.

Your response model could have default values, like:

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (or `str | None = None` in Python 3.10) has a default of `None`.
* `tax: float = 10.5` has a default of `10.5`.
* `tags: List[str] = []` has a default of an empty list: `[]`.

Seu modelo de resposta pode ter valores padrão, como:

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (ou `str | None = None` no Python 3.10) tem um padrão de `None`.
* `tax: float = 10.5` tem um padrão de `10.5`.
* `tags: List[str] = []` tem um padrão de uma lista vazia: `[]`.