from typing import Optional, Union

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

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class ExtendedItem(Item):
    age: int


@app.post("/items/")
def save_union_different_body(item: Union[ExtendedItem, Item]):
    return {"item": item}


client = TestClient(app)

```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.9+ 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)):

def process_items(prices: dict[str, float]):
    for item_name, item_price in prices.items():
        print(item_name)

from typing import Optional

from pydantic import BaseModel


class User(BaseModel):
    name: str

from fastapi import FastAPI

app = FastAPI()


@app.get("/files/{file_path:path}")
async def read_file(file_path: str):

    return mod.html


@pytest.fixture(name="client")
def get_client(mod: ModuleType):
    client = TestClient(mod.app)

    return client


def test_get(client: TestClient, html: str):
    response = client.get("/")
    assert response.text == html


def test_websocket_handle_disconnection(client: TestClient):
    with (
        client.websocket_connect("/ws/1234") as connection,

    ],
)
def get_mod_path(request: pytest.FixtureRequest):
    mod_path = f"docs_src.settings.{request.param}"
    return mod_path


@pytest.fixture(name="main_mod")
def get_main_mod(mod_path: str) -> ModuleType:
    main_mod = importlib.import_module(f"{mod_path}.main")
    return main_mod


def test_settings(main_mod: ModuleType, monkeypatch: MonkeyPatch):
    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")

			}
		}

		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")

## Classes as dependencies { #classes-as-dependencies_1 }

You might notice that to create an instance of a Python class, you use that same syntax.

For example:

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


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

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

Você deve ter percebido que para criar um instância de uma classe em Python, a mesma sintaxe é utilizada.

Por exemplo:

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


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

Nesse caso,  `fluffy` é uma instância da classe `Cat`.

E para criar `fluffy`, você está "chamando" `Cat`.