关于不完整的base64编码，导致的报错问题

报错1：

 Error: Incorrect padding     # base64编码不完整

报错2：

UnicodeDecodeError: 'utf-8' codec can't decode bytes in position 99-100: invalid continuation byte   # utf-8编码中还有不可识别的编码

#!usr/bin/env python
# coding:utf-8
import base64
import chardet

s = b'5Y+v5Lul6K+05piv5peg5omA5LiN6IO977yM57G75Ly85LqO5L2g5bey57uP6Kej5byA6L+Z5Liq5Yqg5a+G77yM5Zyo6L+Z5Liq6L+H56iL5Lit77yM5L2g5bCx6IO95piO55**77yM6buR5a6i5Zyo6Ieq5bex5omA5o6M5o+h55qE5oqA5pyv5LmL5YaF77yM5Y+v5Lul5YGa5b6I5aSa5LqL5oOF'
missing_padding = 4 - len(s) % 4    # 解决不完整编码问题
if missing_padding:
    s += b'=' * missing_padding

b = base64.b64decode(s)
print(str(b, "utf-8", "ignore"))     # "ignore"  解决混杂其他编码问题