def METHOD_NAME(cls, info: ResolveInfo, instance, channel_slug, old_email):
    assign_user_gift_cards(instance)
    match_orders_with_new_user(instance)
    manager = get_plugin_manager_promise(info.context).get()
    notifications.send_user_change_email_notification(
        old_email, instance, manager, channel_slug=channel_slug
    )
    cls.call_event(manager.customer_updated, instance)
    cls.call_event(manager.account_email_changed, instance)