Python Twitter API TwitterError: user_id must be type int

I'm trying to use python-twitter. I'm following this tutorial.

Here is my code:

tweet = cache.get('tweet')

if not tweet:
    tweet = twitter.Api().GetUserTimeline(settings.TWITTER_USER)[0]
    tweet.date = datetime.strptime(tweet.created_at, "%a %b %d %H:%M:%S +0000 %Y")
    cache.set('tweet', tweet, settings.TWITTER_TIMEOUT)

But I'm getting next error:

Twitter.error.TwitterError: {'message': '"user_id" must be type int'}

I've set the variables like in the tutorial:

TWITTER_USER = 'CaseyNeistat'
TWITTER_TIMEOUT = 3600

Is there anything I'm doing wrong?

The article got created about 9 years ago. So the API could changed many times since then.

Here is the signature of the function from python-twitter documentation:

GetUserTimeline(user_id=None, screen_name=None, since_id=None, max_id=None, count=None, include_rts=True, trim_user=False, exclude_replies=False)

So you want to do GetUserTimeline(screen_name=settings.TWITTER_USER)

Otherwise your string would go as user_id.