def METHOD_NAME(self, obj):
    follow_up_query_set = []
    for document in obj.documents.all():
        follow_up_query_set.extend(
            document.follow_ups.filter(for_user=True))
    note_list = list(map(lambda item: {
        "note": item.note,
        "created_at": item.created_at.isoformat(),
    }, follow_up_query_set))
    return note_list