"type": "string",
                            "format": "date-time",
                        },
                        "repeat_at": IsDict(
                            {
                                "title": "Repeat At",
                                "anyOf": [
                                    {"type": "string", "format": "time"},
                                    {"type": "null"},

After you have tests, then you can upgrade the **FastAPI** version to a more recent one, and make sure that all your code is working correctly by running your tests.

If everything is working, or after you make the necessary changes, and all your tests are passing, then you can pin your `fastapi` to that new recent version.

## About Starlette

You shouldn't pin the version of `starlette`.

    process_after: timedelta = Body(),
    repeat_at: Union[time, None] = Body(default=None),
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,
        "repeat_at": repeat_at,
        "start_process": start_process,

                            "type": "string",
                            "format": "date-time",
                        },
                        "repeat_at": IsDict(
                            {
                                "title": "Repeat At",
                                "anyOf": [
                                    {"type": "string", "format": "time"},
                                    {"type": "null"},

    process_after: Annotated[timedelta, Body()],
    repeat_at: Annotated[Union[time, None], Body()] = None,
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,
        "repeat_at": repeat_at,
        "start_process": start_process,

            || this.progressLength;
        const progressChar = line.getAttribute(`${this.pfx}-progressChar`)
            || this.progressChar;
        const chars = progressChar.repeat(progressLength);
		const progressPercent = line.getAttribute(`${this.pfx}-progressPercent`)
			|| this.progressPercent;
        line.textContent = '';
        this.container.appendChild(line);

    ```

=== "Python 3.8+"

    ```Python hl_lines="14"
    {!> ../../../docs_src/body_nested_models/tutorial002.py!}
    ```

## Set types

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

=== "Python 3.10+"

    ```Python hl_lines="12"

    process_after: timedelta = Body(),
    repeat_at: time | None = Body(default=None),
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,
        "repeat_at": repeat_at,
        "start_process": start_process,

    process_after: Annotated[timedelta, Body()],
    repeat_at: Annotated[time | None, Body()] = None,
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,
        "repeat_at": repeat_at,
        "start_process": start_process,

    process_after: Annotated[timedelta, Body()],
    repeat_at: Annotated[Union[time, None], Body()] = None,
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,
        "repeat_at": repeat_at,
        "start_process": start_process,