def checkdate(func):
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        for i in args:
            if len(i) == 0:
                raise ValueError('数据为空')

        return func(*args, **kwargs)
    return wrapper

@checkdate
def safe_base64_decode(s):
    l = len(s)%4
    if l == 0:
        "输入的数据中有 == "
        anw = base64.b64decode(s)
    else:
        if isinstance(s, bytes):
            s = s.decode()
            s = s + '='*l
            anw = base64.b64decode(s)
        else:
            anw = base64.b64decode(s + '='*l)
    return anw