def METHOD_NAME(waypoint: FlightWaypoint, depart_prefix: str) -> str:
    if waypoint.tot is not None:
        time = timedelta(seconds=int(waypoint.tot.total_seconds()))
        return f"T+{time} "
    elif waypoint.departure_time is not None:
        time = timedelta(seconds=int(waypoint.departure_time.total_seconds()))
        return f"{depart_prefix} T+{time} "
    return ""