def decide_which_users_to_annotate(centrality_vector,
                                   number_to_annotate,
                                   already_annotated,
                                   node_to_id):
    centrality_vector = np.asarray(centrality_vector)
    ind = np.argsort(np.squeeze(centrality_vector))
    if centrality_vector.size > 1:
        reversed_ind = ind[::-1]
    else:
        reversed_ind = list()
        reversed_ind = reversed_ind.append(ind)
    user_id_list = list()
    append_user_id = user_id_list.append
    counter = 0
    for node in reversed_ind:
        user_twitter_id = node_to_id[node]
        if user_twitter_id not in already_annotated:
            append_user_id(user_twitter_id)
            counter += 1
            if counter >= number_to_annotate:
                break
    return user_id_list