def add_tweets(self, user, party):
"""
Downloads tweets from a single Twitter user up to the specified ID.
:param user: the Twitter handle of the user.
:param party: the political party to which `user` belongs.
:return the list of downloaded tweets.
"""
query = Query(**self.oauth)
tweets = query.get_user_timeline(
screen_name=user,
count=200,
exclude_replies='false',
include_rts='true')
self.tweets[user] = tweets
self.save()
self.users[user] = party
return tweets
