* 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)

* 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`.

│   │   ├── items.py     # "items" submodule, e.g. import app.routers.items
│   │   └── users.py     # "users" submodule, e.g. import app.routers.users
│   └── internal         # "internal" is a "Python subpackage"
│       ├── __init__.py  # makes "internal" a "Python subpackage"
│       └── admin.py     # "admin" submodule, e.g. import app.internal.admin
```

## `APIRouter`

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:

* O arquivo `app/routers/items.py` está dentro de um pacote, `app/routers/`, portanto, é um "submódulo": `app.routers.items`.
* O mesmo com `app/routers/users.py`,  ele é outro submódulo: `app.routers.users`.
* Há também um subdiretório `app/internal/` com outro arquivo `__init__.py`, então ele é outro "subpacote Python":`app.internal`.
* E o arquivo `app/internal/admin.py` é outro submódulo: `app.internal.admin`.

<img src="/img/tutorial/bigger-applications/package.svg">

{!> ../../docs_src/body_nested_models/tutorial005.py!}
```

////

The string will be checked to be a valid URL, and documented in JSON Schema / OpenAPI as such.

## Attributes with lists of submodels

You can also use Pydantic models as subtypes of `list`, `set`, etc.:

//// tab | Python 3.10+

```Python hl_lines="18"
{!> ../../docs_src/body_nested_models/tutorial006_py310.py!}
```

////

    `TF_Run`, `TF_SessionRun`, `TF_SetAttrTensor` etc.
*   Renamed `tf.image.per_image_whitening()` to
    `tf.image.per_image_standardization()`
*   Move Summary protobuf constructors to `tf.summary` submodule.
*   Deprecate `histogram_summary`, `audio_summary`, `scalar_summary`,
    `image_summary`, `merge_summary`, and `merge_all_summaries`.
*   Combined `batch_*` and regular version of linear algebra and FFT ops. The

        }

        // So now we have an url of the form file://<path>

        // We want to eliminate any relative path nonsense and lock down the path so we
        // need to fully resolve it before any submodules use the path. This can happen
        // when you are using a custom settings.xml that contains a relative path entry
        // for the local repository setting.

                name=response_name,
                type_=self.response_model,
                mode="serialization",
            )
            # Create a clone of the field, so that a Pydantic submodel is not returned
            # as is just because it's an instance of a subclass of a more limited class
            # e.g. UserInDB (containing hashed_password) could be a subclass of User