def get_straight_contour(lanes, extra_lateral) -> List:
    """
    Get several points as bounding box of this road
    :param lanes: lanes contained in road
    :param extra_lateral: extra length in lateral direction, usually sidewalk
    :return: points
    :param lanes:
    :return:
    """
    ret = []
    for lane, dir in [(lanes[0], -1), (lanes[-1], 1)]:
        ret.append(lane.position(0.1, dir * (lane.width / 2.0 + extra_lateral)))
        ret.append(lane.position(lane.length - 0.1, dir * (lane.width / 2.0 + extra_lateral)))
    return ret

    Get several points as bounding box of this road
    :param lanes: lanes contained in road
    :param extra_lateral: extra length in lateral direction, usually sidewalk
    :return: points
    :param lanes:
    :return:
    
metadrive/utils/pg/utils.py