items["bar"] = {"name": "Tenders"}
    yield
    # clean up items
    items.clear()


app = FastAPI(lifespan=lifespan)


@app.get("/items/{item_id}")
async def read_items(item_id: str):
    return items[item_id]


def test_read_items():
    # Before the lifespan starts, "items" is still empty
    assert items == {}

    with TestClient(app) as client:

```

那它就是一個「callable」。

## 以類別作為相依性 { #classes-as-dependencies_1 }

你可能已經注意到，建立一個 Python 類別的實例時，你用的語法也是一樣的。

例如：

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

在這個例子中，`fluffy` 是 `Cat` 類別的一個實例。

而要建立 `fluffy`，你其實是在「呼叫」`Cat`。

所以，Python 類別本身也是一種 **callable**。

```Python
from datetime import date

from pydantic import BaseModel

# 변수를 str로 선언합니다
# 그리고 함수 내부에서 편집기 지원을 받습니다
def main(user_id: str):
    return user_id


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

그 다음 다음과 같이 사용할 수 있습니다:

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

second_user_data = {

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool | None = None


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


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


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

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize", tokenUrl="token", 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")
    assert response.status_code == 401, response.text

For that, we update the Pydantic model `TokenData` with a new property `scopes`.

By validating the data with Pydantic we can make sure that we have, for example, exactly a `list` of `str` with the scopes and a `str` with the `username`.

Instead of, for example, a `dict`, or something else, as it could break the application at some point later, making it a security risk.

        fmt = req.getParameter("fmt");
        if (fmt == null) {
            fmt = "col";
        }
        sort = 0;
        if ((str = req.getParameter("sort")) == null || str.equals("name")) {
            sort = 0;
        } else if (str != null) {
            switch (str) {
            case "size":
                sort = 1;
                break;
            case "type":
                sort = 2;

   *
   * {@snippet :
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()

			}
		}

		str := getUserAgent(testCase.mode)
		expectedStr := testCase.expectedStr
		if IsDocker() {
			expectedStr = strings.ReplaceAll(expectedStr, "; source", "; docker; source")
		}
		if !strings.Contains(str, expectedStr) {
			t.Errorf("Test %d: expected: %s, got: %s", i+1, expectedStr, str)
		}
		os.Unsetenv("MARATHON_APP_LABEL_DCOS_PACKAGE_VERSION")

from unittest.mock import patch

from fastapi import FastAPI
from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient
from pydantic import BaseModel


class Item(BaseModel):
    name: str
    price: float


app = FastAPI()


@app.get("/default")
def get_default() -> Item:
    return Item(name="widget", price=9.99)


@app.get("/explicit", response_class=JSONResponse)