使用自动例子BollChannelStrategy.py回测，查看回测K线图上没有绘制boll线，变量改成xxx0、xxx1、xxx_line格式也不显示，请问4.1.0版本该如何叠加K线绘制变量和小窗口绘制变量？
variables = [
"boll_mid0", "boll_mid1",
"boll_upper0", "boll_upper1",
"boll_lower0", "boll_lower1",
"atr_line",
"candle_count"
]