* The file `app/routers/items.py` is inside a package, `app/routers/`, so, it's a submodule: `app.routers.items`.
* The same with `app/routers/users.py`, it's another submodule: `app.routers.users`.
* There's also a subdirectory `app/internal/` with another file `__init__.py`, so it's another "Python subpackage": `app.internal`.
* And the file `app/internal/admin.py` is another submodule: `app.internal.admin`.

  )

# Add Keras module aliases
_losses = _KerasLazyLoader(globals(), submodule="losses", name="losses")
_metrics = _KerasLazyLoader(globals(), submodule="metrics", name="metrics")
_optimizers = _KerasLazyLoader(
    globals(), submodule="optimizers", name="optimizers")
_initializers = _KerasLazyLoader(
    globals(), submodule="initializers", name="initializers")
setattr(_current_module, "losses", _losses)

## Pydantic v1 in v2 { #pydantic-v1-in-v2 }

Pydantic v2 includes everything from Pydantic v1 as a submodule `pydantic.v1`. But this is no longer supported in versions above Python 3.13.

This means that you can install the latest version of Pydantic v2 and import and use the old Pydantic v1 components from this submodule, as if you had the old Pydantic v1 installed.

{* ../../docs_src/pydantic_v1_in_v2/tutorial001_an_py310.py hl[1,4] *}

setattr(_current_module, "flags", flags)

_major_api_version = 1

# Add module aliases from Keras to TF.
# Some tf endpoints actually lives under Keras.
_current_module.layers = _KerasLazyLoader(
    globals(),
    submodule="__internal__.legacy.layers",
    name="layers",
    mode="v1")
if _tf_uses_legacy_keras:
  _module_dir = _module_util.get_parent_dir_for_name(
      "tf_keras.api._v1.keras.__internal__.legacy.layers")
else:

* recap (noun): резюме
* utility function: вспомогательная функция
* fast to code: позволяет быстро писать код
* Tutorial - User Guide: Учебник - Руководство пользователя
* submodule: подмодуль
* subpackage: подпакет
* router: роутер
* building, deploying, accessing (when describing features of FastAPI Cloud): созданиe образа, развертывание и доступ
* type checker tool: инструмент проверки типов

* Das Gleiche gilt für `app/routers/users.py`, es ist ein weiteres Submodul: `app.routers.users`.
* Es gibt auch ein Unterverzeichnis `app/internal/` mit einer weiteren Datei `__init__.py`, es handelt sich also um ein weiteres „Python-Subpackage“: `app.internal`.
* Und die Datei `app/internal/admin.py` ist ein weiteres Submodul: `app.internal.admin`.

### 이름 충돌 피하기 { #avoid-name-collisions }

submodule `items`를 직접 import하고, 그 안의 `router` 변수만 import하지는 않습니다.

이는 submodule `users`에도 `router`라는 이름의 변수가 있기 때문입니다.

만약 다음처럼 순서대로 import했다면:

```Python
from .routers.items import router
from .routers.users import router
```

`users`의 `router`가 `items`의 `router`를 덮어써서 동시에 사용할 수 없게 됩니다.

따라서 같은 파일에서 둘 다 사용할 수 있도록 submodule들을 직접 import합니다:

│   │   ├── items.py     # "items" submodule'ü, örn. import app.routers.items
│   │   └── users.py     # "users" submodule'ü, örn. import app.routers.users
│   └── internal         # "internal" bir "Python subpackage"idir
│       ├── __init__.py  # "internal"ı bir "Python subpackage" yapar
│       └── admin.py     # "admin" submodule'ü, örn. import app.internal.admin
```

## `APIRouter` { #apirouter }

Todo eso, de manera arbitraria.

### Definir un submodelo { #define-a-submodel }

Por ejemplo, podemos definir un modelo `Image`:

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[7:9] *}

### Usar el submodelo como tipo { #use-the-submodel-as-a-type }

Y luego podemos usarlo como el tipo de un atributo:

* Lo mismo con `app/routers/users.py`, es otro submódulo: `app.routers.users`.
* También hay un subdirectorio `app/internal/` con otro archivo `__init__.py`, por lo que es otro "subpaquete de Python": `app.internal`.
* Y el archivo `app/internal/admin.py` es otro submódulo: `app.internal.admin`.