from typing import OrderedDict


def group_tweets_by_screen_name(tweet_list):
    """Return dict of tweet lists grouped by user screen_name"""
    d = OrderedDict()
    for tweet in tweet_list:
        screen_name = '@'+tweet.user.screen_name
        if screen_name in d:
            d[screen_name].append(tweet)
        else:
            d[screen_name] = [tweet]
    return d