from aiogram.types import CallbackQuery
from aiogram_dialog import DialogManager
from aiogram_dialog.widgets.kbd import Select


async def on_event_selected(
    callback: CallbackQuery,
    widget: Select,
    manager: DialogManager,
    item_id: str,
):
    manager.dialog_data["selected_event"] = item_id
    await manager.next()

async def change_registration():
    ...