def on_tick(self, tick: TickData):
    """
    Callback of new tick data update.
    """
    if (
        self.last_tick_time
        and self.last_tick_time.minute != tick.datetime.minute
    ):
        bars = {}
        for vt_symbol, bg in self.bgs.items():
            bars[vt_symbol] = bg.generate()
        self.on_bars(bars)

    bg: BarGenerator = self.bgs[tick.vt_symbol]
    bg.update_tick(tick)

    self.last_tick_time = tick.datetime

bg: BarGenerator = self.bgs[tick.vt_symbol]和bg.update_tick(tick)最后这两行里的bg为什么不是self.bgs，好像更新的tick传到bg里了也没传到self.bgs里啊

self.bgs是个字典，无法直接update_tick。

另外这个传递的规则建议学下Python的基础语法