I need a Python developer to fetch 50-level market depth for 20 FUTURES AND OPTIONS instruments. The incoming order-book snapshots must be written to excel .csv file continuously so I can query them later for research and back-testing. Process: Login to FYERS api - auto login setup (if possible) using authenticator (PYOTP). If not possible then generate the access token using redirect url and save it in file for later use. Initially NIFTY index and BANKNIFTY index, live data to be fetched using websocket, then using the live data we will make OPTION and FUTURE instruments using certain formulas, then we will fetch the market depth (50 level) of those instruments. Finally store that data continuously in .csv excel file. Please note that separate file name(instrument and date) to be used to save data for each instrument. Deliverables 1. Clean, well-commented source code that subscribes to full market depth and writes every level update to a .csv file.