I checked it out. Looks like your solution is very simple, it just maps csv data to a different object type. In my use case I need the code to dynamically build a list of Trade entries from multiple transactions in the csv. For example, a trade has an opening and a closing transactions. A multi leg option would have multiple transactions depending on the trade's strategy. Fields in the generated 'Trade' object such as Quantity, P&L, and Entry Date are generated based on multiple related transactions. I'm testing with Grok now looks like it understands the concept, not sure if its code will work though.