def add_tracks_to_playlist(spotify_obj, spotify_username, playlist_id, tracks_ids,
                           tracks_per_requests=100):
    """Method that adds tracks with given Spotify tracks IDs to Spotify user's playlist
    with a given playlist ID. Spotipy.Spotify object is used to add the tracks.
    Maximum tracks per request in Spotify API is 100 and the same number is set in the method
    by default. Can be changed to a number below 100."""
    results = []
    for tracks_chunk in [tracks_ids[i:i + tracks_per_requests] for i in
                         range(0, len(tracks_ids), tracks_per_requests)]:
        results.append(spotify_obj.user_playlist_add_tracks(spotify_username,
                                                        playlist_id,
                                                        tracks_chunk))
    return results