Customized csv to feed in DataFactory, with backtrader strategies in paper testing


I want to clean and process all indicators outside of backtrader functions (personal preference). This can be done in backtrader as I can expand on bt.feeds.PandasData and use for loop to load multiple stock datas. However, when using the alpaca_backtrader_api package, I didn’t know how to load customized data from local csv. The reason why I want to use backtrader as it is handy in terms of indicator logic managemet and convenient logs. Are there any existing examples? I was inspired by this one but it does not show how to load from historical csv. Thanks.