Updating a Python Program to import/process FTP inventory files

I recently had a Freelancer write me a program to pull ecommerce inventory files from various vendors' FTP sites, process/analyze that information, and then publish to a results file. I need to add some additional information to that list as well as some additional vendors. Current work flow for each vendor: Retrieve product file & inventory file from vendor Match up product information (manufacturer/part number) with inventory levels Write inventory levels to corresponding cell of output csv In this update, I would like to add a 5 additional vendors. I would like to introduce some additional functionality so that the application brings in pricing information as well. The existing application works beautifully, the original programmer is just consumed in a full-time project at the moment. There will be no "repair" of the existing code necessary, only adding to it. See the application files attached. Example files for everything you will be working with are available upon request. The current program runs on a local machine with an output csv file ~40mb.