[python]为什么父类的值没有改变

在调式中已经发现第二次初始化worker的时候，worker的name已经为lisi了，为什么打印结果仍然是111，新手望拍砖指导。

父类

class worker(object):
    '''
    classdocs
    '''
    name="111"
    salary=""

    def __init__(self,name,salary):
        self.name=name
        self.salary=salary
        #print self.name,self.salary
        
    def work(self):
        print "I'm working"
        

子类

from worker import worker
class Tester(worker):
    '''
    classdocs
    '''
    name=""
    salary=""
    sex=""

    def __init__(self,name,salary,sex):
        worker(name,salary)
        self.name=name
        self.salary=salary
        self.sex=sex
        
    def boring(self):
        worker.work(self)
        print self.name,self.salary,self.sex
        

调用类：

from com.dianxinos.model.worker import worker
from com.dianxinos.model.Tester import Tester
class Hello:
    def __init__(self):
        #reload()
        oneworker= worker("zhangsan","5000")
        oneworker.work()
        print oneworker.name,oneworker.salary
    def test(self):
        tester=Tester("lisi","10000","man")
        tester.work()
        #tester.boring()
        print tester.name,tester.salary,tester.sex
        print super(Tester, tester).name
   
        
if __name__ == "__main__"  :
    h=Hello()
    h.test()

打印结果：

I'm working
zhangsan 5000
I'm working
lisi 10000 man
111
111