python类中出现NameError的问题

报的错如下：

class UserInfo(bidderID, name, addr, port):
NameError: name 'bidderID' is not defined

代码如下：

class UserInfo(bidderID, name, addr, port):

        bidderID = 0        #用户ID
        name = ''           #用户名

        addr = ''           #IP地址
        port = 0            #端口号

        rname = ''          #所在竞拍室名称
        bidprice = 0            #出价

    #UserInfo next = null

        def _init_(self, bidderID, name, addr, port):
                self.bidderID = bidderID
                self.name = name
                self.addr = addr
                self.port = port


    #打印用户关键信息,并返回包含用户信息的字符串
        def printUserInfo(self):
                str = "\t用户ID: " + bidderID + "\t用户名: " + name + "\t出价: " + bidprice + "\n"
                return str

U=UserInfo(1,"Alice","10.10.10.0",1)
U.printUserInfo()

求问怎么回事？怎么解决？

---

class(object):
pass
类定义错误了，类名后面是继承，你却写成了初始化里面去了！低级错误