栗子：编程开发人员学 Python 的话，学习效率很高，默认为1。
而且，job 的属性为 programmer。
class Student:
def __init__(self,name,job=None,time=0.00,time_effective=0.00):
self.name=name
self.job=job
self.time=time
self.time_effective=time_effective
def count_time(self,hour,rate):
self.time+=hour
self.time_effective+=hour*rate
class Programmer(Student):
def __init__(self,name):
Student.__init__(self,name,job=‘programmer‘,time=0.00,time_effctive=0.00)
def count_time(self,hour):
Student.count_time(self,hour,rate=1)
student1=Student(‘韩梅梅‘)
student2=Programmer(‘李华‘)
print(student1.job)
print(student2.job)
student1.count_time(10.0,0.8)
student2.count_time(10)
print(student1.time_effective)
print(student2.time_effective)
原文：https://www.cnblogs.com/Macfee/p/11342226.html