```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial008b.py!}
```

////

In both cases this means that `item` could be an `int` or a `str`.

#### Possibly `None`

You can declare that a value could have a type, like `str`, but that it could also be `None`.

In Python 3.6 and above (including Python 3.10) you can declare it by importing and using `Optional` from the `typing` module.

</div>

#### Generate Client Code

To generate the client code you can use the command line application `openapi-ts` that would now be installed.

Because it is installed in the local project, you probably wouldn't be able to call that command directly, but you would put it on your `package.json` file.

It could look like this:

```JSON  hl_lines="7"
{
  "name": "frontend-app",
  "version": "1.0.0",
  "description": "",

Now, let's see how you could use that to return a custom response.

Let's say that you want to return an <a href="https://en.wikipedia.org/wiki/XML" class="external-link" target="_blank">XML</a> response.

.forEach((htmlElement) => $(htmlElement).off(EVENT_KEY))\n\n    /**\n     * `document` has 2 events `Event.FOCUSIN` and `Event.CLICK_DATA_API`\n     * Do not move `document` in `htmlElements` array\n     * It will remove `Event.CLICK_DATA_API` event that should remain\n     */\n    $(document).off(Event.FOCUSIN)\n\n    $.removeData(this._element, DATA_KEY)\n\n    this._config              = null\n    this._element             = null\n    this._dialog              = null\n    this._backdrop            = null\n...

    # For coverage
    # TODO: in theory this would allow declaring types that could be lists of bytes
    # to be read from files and other types, but I'm not even sure it's a good idea
    # to support it as a first class "feature"
    assert is_bytes_sequence_annotation(Union[List[str], List[bytes]])


def test_is_uploadfile_sequence_annotation():
    # For coverage

///

And then the `admin_email` setting would be set to `"******@****.***"`.

The `app_name` would be `"ChimichangApp"`.

And the `items_per_user` would keep its default value of `50`.

## Settings in another module

   * FeatureSpecificTestSuiteBuilder.suppressing()}.
   */
  /*
   * TODO(cpovirk): or we could make HOLES_FORBIDDEN a feature. Or we could declare that
   * implementations are permitted to throw IAE if a hole is requested, and we could update
   * test*Hole to permit IAE. (But might this ignore genuine bugs?) But see the TODO above
   * testLower, which could make this all unnecessary
   */
  public static Method[] getHoleMethods() {

Depending on your use case, you might prefer to use a different library, but if you asked me, I would probably suggest you try **Strawberry**.

Here's a small preview of how you could integrate Strawberry with FastAPI:

{* ../../docs_src/graphql/tutorial001.py hl[3,22,25:26] *}

### Import `APIRouter`

You import it and create an "instance" the same way you would with the class `FastAPI`:

```Python hl_lines="1  3" title="app/routers/users.py"
{!../../docs_src/bigger_applications/app/routers/users.py!}
```

### *Path operations* with `APIRouter`

And then you use it to declare your *path operations*.

Use it the same way you would use the `FastAPI` class:

CLASS_NAME_COLLAPSED) {\n      if (this._options.noTransitionAfterReload) {\n        $body.addClass('hold-transition').addClass(CLASS_NAME_COLLAPSED).delay(50).queue(function () {\n          $(this).removeClass('hold-transition')\n          $(this).dequeue()\n        })\n      } else {\n        $body.addClass(CLASS_NAME_COLLAPSED)\n      }\n    } else if (this._options.noTransitionAfterReload) {\n      $body.addClass('hold-transition').removeClass(CLASS_NAME_COLLAPSED).delay(50).queue(function () {\n        $...