python正则检查邮件地址格式

#!/usr/bin/pythonimport re,sysmail = sys.argv[1]def mailcheck(mail):    reStr = '[a-zA-Z0-9]+[\-\._]?[a-zA-Z0-9]+@([a-zA-Z0-9]+\.)+[a-zA-Z]{1,3}$'    if re.match(reStr, mail):        return True    else:        return Falseif mailcheck(mail):    print "OK"