请帮我将这段代码改为设置4个固定的NPC代码# Spawn vehicles # -------------- batch = [] for n, transform in enumerate(spawn_points): print('n',n) print('transform',transform) if n >= args.number_of_vehicles: break blueprint = random.choice(blueprints) print('blueprints的长度', len(blueprints)) print('blueprints',blueprints) print('blueprint', blueprint) if blueprint.has_attribute('color'): color = random.choice(blueprint.get_attribute('color').recommended_values) blueprint.set_attribute('color', color) if blueprint.has_attribute('driver_id'): driver_id = random.choice(blueprint.get_attribute('driver_id').recommended_values) blueprint.set_attribute('driver_id', driver_id) blueprint.set_attribute('role_name', 'autopilot') # prepare the light state of the cars to spawn light_state = vls.NONE if args.car_lights_on: light_state = vls.Position | vls.LowBeam | vls.LowBeam # spawn the cars and set their autopilot and light state all together batch.append(SpawnActor(blueprint, transform) .then(SetAutopilot(FutureActor, True, traffic_manager.get_port())) .then(SetVehicleLightState(FutureActor, light_state))) for response in client.apply_batch_sync(batch, synchronous_master): if response.error: logging.error(response.error) else: vehicles_list.append(response.actor_id)

你可以使用以下代码设置4个固定的NPC车辆：

# Spawn vehicles
# --------------
batch = []

# Define the spawn points for the NPC vehicles
spawn_points = [
    carla.Transform(carla.Location(x=10, y=10, z=0), carla.Rotation()),
    carla.Transform(carla.Location(x=20, y=20, z=0), carla.Rotation()),
    carla.Transform(carla.Location(x=30, y=30, z=0), carla.Rotation()),
    carla.Transform(carla.Location(x=40, y=40, z=0), carla.Rotation())
]

for n, transform in enumerate(spawn_points):
    if n >= 4:  # Spawn only 4 NPC vehicles
        break
    
    blueprint = random.choice(blueprints)
    if blueprint.has_attribute('color'):
        color = random.choice(blueprint.get_attribute('color').recommended_values)
        blueprint.set_attribute('color', color)
    if blueprint.has_attribute('driver_id'):
        driver_id = random.choice(blueprint.get_attribute('driver_id').recommended_values)
        blueprint.set_attribute('driver_id', driver_id)
    blueprint.set_attribute('role_name', 'autopilot')

    # prepare the light state of the cars to spawn
    light_state = vls.NONE
    if args.car_lights_on:
        light_state = vls.Position | vls.LowBeam | vls.LowBeam

    # spawn the cars and set their autopilot and light state all together
    batch.append(SpawnActor(blueprint, transform)
                 .then(SetAutopilot(FutureActor, True, traffic_manager.get_port()))
                 .then(SetVehicleLightState(FutureActor, light_state)))

for response in client.apply_batch_sync(batch, synchronous_master):
    if response.error:
        logging.error(response.error)
    else:
        vehicles_list.append(response.actor_id)

在这里，我们手动定义了4个NPC车辆的初始位置，并将其存储在`spawn_points`列表中。然后，我们遍历`spawn_points`列表，仅生成4个NPC车辆。每个NPC车辆的蓝图和外观随机选择，但我们将其角色设置为“autopilot”，以使其自动驾驶。最后，我们将生成的NPC车辆的ID存储在`vehicles_list`列表中。