python正则检测密码合法性

客户系统升级，要求用户密码符合一定的规则，即：包含大小写字母、数字、符号，长度不小于8,于是先用python写了个简单的测试程序：

#encoding=utf-8

#-------------------------------------------------------------------------------
# Name:        模块1
# Purpose:
#
# Author:      Administrator
#
# Created:     10-06-2014
# Copyright:   (c) Administrator 2014
# Licence:     <your licence>
#-------------------------------------------------------------------------------
import re

def checklen(pwd):
    return len(pwd)>=8

def checkContainUpper(pwd):
    pattern = re.compile('[A-Z]+')
    match = pattern.findall(pwd)

    if match:
        return True
    else:
        return False

def checkContainNum(pwd):
    pattern = re.compile('[0-9]+')
    match = pattern.findall(pwd)
    if match:
        return True
    else:
        return False

def checkContainLower(pwd):
    pattern = re.compile('[a-z]+')
    match = pattern.findall(pwd)

    if match:
        return True
    else:
       return False

def checkSymbol(pwd):
    pattern = re.compile('([^a-z0-9A-Z])+')
    match = pattern.findall(pwd)

    if match:
        return True
    else:
        return False

def checkPassword(pwd):

    #判断密码长度是否合法
    lenOK=checklen(pwd)

    #判断是否包含大写字母
    upperOK=checkContainUpper(pwd)

    #判断是否包含小写字母
    lowerOK=checkContainLower(pwd)

    #判断是否包含数字
    numOK=checkContainNum(pwd)

    #判断是否包含符号
    symbolOK=checkSymbol(pwd)

    print(lenOK)
    print(upperOK)
    print(lowerOK)
    print(numOK)
    print(symbolOK)
    return (lenOK and upperOK and lowerOK and numOK and symbolOK)

def main():
    if checkPassword('Helloworld#123'):
        print('检测通过')
    else:
        print('检测未通过')

if __name__ == '__main__':
    main()

平时用正则不多，不知道怎么写一个正则满足要求，用了比较笨的办法，谁知道一句正则检验的请赐教!