def get_session():
    with Session(engine) as session:
        yield session


def get_user(user_id: int, session: Annotated[Session, Depends(get_session)]):
    user = session.get(User, user_id)
    if not user:
        raise HTTPException(status_code=403, detail="Not authorized")
    session.close()


def generate_stream(query: str):
    for ch in query:
        yield ch
        time.sleep(0.1)

### Функция lifespan { #lifespan-function }

Первое, на что стоит обратить внимание, — мы определяем асинхронную функцию с `yield`. Это очень похоже на Зависимости с `yield`.

{* ../../docs_src/events/tutorial003_py39.py hl[14:19] *}

Первая часть функции, до `yield`, будет выполнена до запуска приложения.

А часть после `yield` будет выполнена после завершения работы приложения.

### Асинхронный менеджер контекста { #async-context-manager }

    pass


async def asyncgen_state(state: dict[str, str] = Depends(get_state)):
    state["/async"] = "asyncgen started"
    yield state["/async"]
    state["/async"] = "asyncgen completed"


def generator_state(state: dict[str, str] = Depends(get_state)):
    state["/sync"] = "generator started"
    yield state["/sync"]
    state["/sync"] = "generator completed"

def get_session():
    with Session(engine) as session:
        yield session


def get_user(user_id: int, session: Annotated[Session, Depends(get_session)]):
    user = session.get(User, user_id)
    if not user:
        raise HTTPException(status_code=403, detail="Not authorized")


def generate_stream(query: str):
    for ch in query:
        yield ch
        time.sleep(0.1)

   * one from the pool. We must take the pooled connection because by taking it from the pool, we've
   * fully acquired it.
   *
   * This test yields threads to force the decision of plan1 to be deliberate and not lucky. In
   * particular, we set up this sequence of events:
   *
   *  1. take plan 0
   *  3. plan 0 connects
   *  4. finish taking plan 1
   *

class Session:
    def __init__(self) -> None:
        self.open = True


async def dep_session() -> Any:
    s = Session()
    yield s
    s.open = False
    global_state = global_context.get()
    global_state["session_closed"] = True


SessionFuncDep = Annotated[Session, Depends(dep_session, scope="function")]

				}

				// if the default concurrency yields zero results, throw an error.
				if throughputHighestResults[i].Downloads == 0 && opts.concurrencyStart == concurrency {
					errStr = fmt.Sprintf("no results for downloads upon first attempt, concurrency %d and duration %s",
						opts.concurrencyStart, opts.duration)
				}

				// if the default concurrency yields zero results, throw an error.

                    yield webConfigService.getWebConfig(id).get();
                }
                case FILE -> {
                    final FileConfigService fileConfigService = ComponentUtil.getComponent(FileConfigService.class);
                    yield fileConfigService.getFileConfig(id).get();
                }
                case DATA -> {

	left, right *Tree[K, V]
	key         K
	value       V
}

func (t *Tree[K, V]) walk(yield func(key K, val V) bool) bool {
	return t == nil || t.left.walk(yield) && yield(t.key, t.value) && t.right.walk(yield)
}

func (t *Tree[K, V]) Walk(yield func(key K, val V) bool) {
	t.walk(yield)
}

// walk tree t in-order
var t Tree[string, int]
for k, v := range t.Walk {

    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: