关于Python 面向对象寻值的问题. How the number be found in the OOP in Python

今天在看Python面向对象的时候看到了一个很有意思的问题

Today. When i learning the OOP in python , I found a very interesting Question that how a number be found in the parent class and the child class .

First of all, let us define a class Animals 

class Animals:
    age = 0

 Then let us define a child class 

class Dog(Animals):
    "Dog class"

 next, we just create a main method :

zhang_san= Dog()
li_si = Dog()
zhang_san.age = 1 
Dog.age = 10
print(zhang_san.age)
print(li_si.age)

We will get a result that the age in zhang_san is absolutely 1 .But how about the age in object li_si ?

Actually the result of li_si is 10.

So why ?

if we also set the value of age of li_si as any numbers such as 99 

The outcome will be different. 

So why ?

As the number of age is a class number , belong to the class of Animals and the dog is the child node of Animals 

When you want to find a number in python . the program will to find the child node in first , if can not find any number you want the python will countine to search according to their parent nodes. At the end of the process , if it is still could not find a number , the program will throw error .