convert an existing python script into a Google AppEngine application

We will provide you with an existing python script (available at [login to view URL]) converting data between two formats. The script is currently used in production as a commandline application. Your task is to convert this script into a Google AppEngine application. The user will upload the input data file and gets a download link for the converted data in return. In addition the user should be able to choose that he wants the data to be added to a Google Docs spreadsheet. The web application needs no styling whatsoever, just the plain HTML forms to make the application work. The same functionality must be provide as a webservice letting the user post the input data via a HTTP POST request. The application must include authentication via Google AppEngine authentication system.