) -> Union[DefaultPlaceholder, DefaultType]:
    """
    Pass items or `DefaultPlaceholder`s by descending priority.

    The first one to _not_ be a `DefaultPlaceholder` will be returned.

    Otherwise, the first item (a `DefaultPlaceholder`) will be returned.
    """
    items = (first_item,) + extra_items
    for item in items:
        if not isinstance(item, DefaultPlaceholder):
            return item

    *, route: routing.APIRoute, method: str
) -> str:  # pragma: nocover
    warnings.warn(
        "fastapi.openapi.utils.generate_operation_id() was deprecated, "
        "it is not used internally, and will be removed soon",
        DeprecationWarning,
        stacklevel=2,
    )
    if route.operation_id:
        return route.operation_id
    path: str = route.path_format