Python数字人民币程序设计未解析的引用

未解析的引用咋弄
def fraction_to_str(num_str):
str_len = len(num_str)
result = ""
for i in range(str_len):
num = int(num_str[i])
result += int_list[num] + fraction_list[i]
return result

https://ask.csdn.net/questions/7731814?spm=1010.2135.3001.5894&answer=53808542&username=weixin_56177871&utm_medium=notify.im.followQuestion.a
这个问题有完整代码