* 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`.

All that, arbitrarily nested.

### Define a submodel { #define-a-submodel }

For example, we can define an `Image` model:

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

### Use the submodel as a type { #use-the-submodel-as-a-type }

And then we can use it as the type of an attribute:

    `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

        * When a `response_model` is declared, the same `response_model` type declaration won't be used as is, it will be "cloned" to create an new one (a cloned Pydantic `Field` with all the submodels cloned as well).