I haven't seen anyone mention this issue for some reason, but in fetch_tweets.py:

  fetch_tweets_from_user(user_name):
      ...
      tweets = api.user_timeline(screen_name=user, count=200, include_rts=False)  

'user' isn't defined, should be user_name, right? Side note, 'copilot' is a decent name for this (though copilots are usually very competent, moreso than this right now). You must check the suggestions carefully. Maybe it'll make folks better at code review, lol.