Day06 关于使用正则表达式统计汉字字频的问题

为什么出来的结果里包含了标点符号？
代码如下：

def stats_text_cn(string):
    import re                                                                       #导入正则表达式模块
    result_cn_interpunction = re.sub('[^\u4e00-\u9fa5]','',string)                  #提取中文字符串
    string = string.replace(' ','').replace('\n','')                                #删除空元素与换行元素
    list1 = re.split('',string)                                                     #将字符串转换为列表list1
    dict1 = {}                                                                      #建立空的字典
    for i in list1:                                                                 #i属于list1中的元素，开始循环
        dict1.setdefault(i,list1.count(i))                                          #将列表中的汉字及汉字的出现次数，分别赋值给dict1的键和值
    tup1 = sorted(dict1.items(),key = lambda items:items[1],reverse = True)         #将dict1按照value值从大到小排列，并将结果赋值给元祖tup1
    return tup1                                                                     #返回tup1的值

result = stats_text_cn(text)
print(result)

Start with the stats_text_cn function shown in the issue and compare the value assigned to result_cn_interpunction with the string passed to re.split. Confirm the expected input and output, then verify that the returned tuples contain only Chinese characters with correct frequency counts.