如何用Python检查密码的有效性

import re 
password = "R@m@_f0rtu9e$"
flag = 0
while True: 
 if (len(password)<8): 
 flag = -1
 break
 elif not re.search("[a-z]", password): 
 flag = -1
 break
 elif not re.search("[A-Z]", password): 
 flag = -1
 break
 elif not re.search("[0-9]", password): 
 flag = -1
 break
 elif not re.search("[_@$]", password): 
 flag = -1
 break
 elif re.search("s", password): 
 flag = -1
 break
 else: 
 flag = 0
 print("有效密码") 
 break
 
if flag ==-1: 
 print("无效密码")

有效密码