Python中re.error: unbalanced parenthesis at position 88

问题：re.error: unbalanced parenthesis at position 88

在使用Python正则表达式的时候，用替换方法出现上述错误，

下面是错误代码：

new_url = "https://cdn.jsdelivr.net/gh/crazyjums/crazyjums.github.io@master/images/article/20191227161526664.png)"
old_url = "https://img2018.cnblogs.com/blog/1212206/201912/1212206-20191227161526664-2133632479.png)"
line = "![list example](https://img2018.cnblogs.com/blog/1212206/201912/1212206-20191227161526664-2133632479.png)"
new_line = re.sub(old_url,new_url,line)
print(new_line)

错误提示：

error

错误原因：

reason

我们可以看到，需要替换的两个字符串末尾多出一个)来，导致匹配出错。我们去掉末尾那个)就可以了。

更正代码：

    line = '![list example](https://img2018.cnblogs.com/blog/1212206/201912/1212206-20191227161526664-2133632479.png)'
    old_url = "https://img2018.cnblogs.com/blog/1212206/201912/1212206-20191227161526664-2133632479.png"
    new_url = "https://cdn.jsdelivr.net/gh/crazyjums/crazyjums.github.io@master/images/article/20191227161526664.png"
    l = re.sub(old_url,new_url,line)
    print(line)
    print(l)

正确运行结果：

right result