import re


def word_tokenizer(sentence):
    """
    将一句话分成单词的列表, 会顺便承担清除标点符号的工作

    Parameters
    ----------
    sentence : string

    Returns
    --------
    words : the list of word
    """
    solve_sentence = re.sub(r'\W+|\s+', ' ', sentence)
    words = solve_sentence.lower().strip(' ').split(' ')
    return words