The following is my attempt to make a custom position sizer based on ATR and the multiplier for the given future. I'm sure this is relatively easy but I seem to have hit a wall.

I seem to have a position size of 0 for every trade.
What am I getting wrong?

Thanks.

class comm_sizer(bt.Sizer):
    def __init__(self, atr):
        #self.atr_parameter= atr_parameter
        atr= self.atr
        risk_per_trade=5000
        atr_risk_per_trade=5
        
        sizing = math.floor((risk_per_trade/(mult*atr_risk_per_trade*atr)))
        
   # position = self.broker.getposition(data)
    
    def _getsizing(self,comminfo,cash,data,isbuy):
        
        return sizing

I have a system where I enter a long position and simultaneously enter a protective stop. I have a separate exit that sometimes occurs. When this occurs, I'd like to be able to cancel the protective stop. I currently use more than one instrument, (currently looking at a basket of 5 stocks), so I'd like to either find a way to determine which orders are still open by symbol or cancel all open orders by symbol.
After looking through the documentation I believe this should be possible but I can't seem to get it to work.
Does anyone have any ideas?

Thanks.