[exe34]

the model is for me. I wrote a crude btc trading bot, and I had three major objects: Market(), TradingStrategy and SimulatedMarket which used historical data.

I did not model individual transactions, fees, etc as objects. The idea was that I encapsulated all the stuff that's relevant to a strategy in one object, and the market object would give me things like get_price(), buy(), sell(), which would also be available in the simulated version.

[abirch]

And if you can encapsulate the 3 different domains well, if you switch brokers you should have any external dependencies. Make your functions/domains deep.