if isinstance(s,str) == True:
        a = len(s) % 4
        if a == 0:
            return base64.b64decode(s)
        else:
            return base64.b64decode(s + '='*(4-a))
    else:
        s_str = s.decode('ascii')
        b = len(s_str) % 4
        if b == 0:
            return base64.b64decode(s_str)
        else:
            return base64.b64decode(s_str + '='*(4-b))