async def context_b(state: dict = Depends(context_a)):
    state["context_b"] = "started b"
    try:
        yield state
    finally:
        state["context_b"] = f"finished b with a: {state['context_a']}"


@app.get("/async")
async def get_async(state: str = Depends(asyncgen_state)):
    return state


@app.get("/sync")
async def get_sync(state: str = Depends(generator_state)):

)
def get_exclude_unset_none() -> ModelDefaults:
    return ModelDefaults(x=None, y="y")


client = TestClient(app)


def test_return_defaults():
    response = client.get("/")
    assert response.json() == {"sub": {}}


def test_return_exclude_unset():
    response = client.get("/exclude_unset")
    assert response.json() == {"x": None, "y": "y"}


def test_return_exclude_defaults():

    owner_ids: Optional[List[int]] = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return Item(aliased_name="coerce", price="1.0")


@app.get("/items/validlist", response_model=List[Item])
def get_validlist():
    return [
        Item(aliased_name="foo"),

app = FastAPI()


@app.post("/form/python-list")
def post_form_param_list(items: list = Form()):
    return items


@app.post("/form/python-set")
def post_form_param_set(items: set = Form()):
    return items


@app.post("/form/python-tuple")
def post_form_param_tuple(items: tuple = Form()):
    return items


client = TestClient(app)


def test_python_list_param_as_form():
    response = client.post(

def test_verify_password():
    assert verify_password("secret", fake_users_db["johndoe"]["hashed_password"])


def test_get_password_hash():
    assert get_password_hash("secretalice")


def test_create_access_token():
    access_token = create_access_token(data={"data": "foo"})
    assert access_token


def test_token_no_sub():
    response = client.get(

```Python hl_lines="2"
@app.get('/')
def results():
    results = some_library()
    return results
```

---

If your application (somehow) doesn't have to communicate with anything else and wait for it to respond, use `async def`.

---

If you just don't know, use normal `def`.

---

class UserInDB(User):
    hashed_password: str


def get_user(db, username: str):
    if username in db:
        user_dict = db[username]
        return UserInDB(**user_dict)


def fake_decode_token(token):
    # This doesn't provide any security at all
    # Check the next version
    user = get_user(fake_users_db, token)
    return user


async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):

    },
}

app = FastAPI()


def fake_hash_password(password: str):
    return "fakehashed" + password


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


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


class UserInDB(User):
    hashed_password: str


def get_user(db, username: str):

    },
}

app = FastAPI()


def fake_hash_password(password: str):
    return "fakehashed" + password


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


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


class UserInDB(User):
    hashed_password: str


def get_user(db, username: str):

class MySuperContextManager:
    def __init__(self):
        self.db = DBSession()

    def __enter__(self):
        return self.db

    def __exit__(self, exc_type, exc_value, traceback):
        self.db.close()


async def get_db():
    with MySuperContextManager() as db: