human
I am working on the file "Note/第二章. 抽象数据类型和 Python 类.ipynb".
The first task is:
私有变量
官方教程：
"Private" instance variables that cannot be accessed except from inside an object don’t exist in Python, However, there is a convention that is followed by most Python program: a name prefixed with an underscore (e.g. _spam) should be treated as a non-public part of the API (whether it is a function, a method or a data member). It should be considered an implementation detail and subject to change without notice. 
在内部，python使用一种name mangling 技术，将 __membername替换成 _classname__membername，所以你在外部使用原来的私有成员的名字时，会提示找不到，可以通过这种方式访问私有变量，但是强烈不建议，因为不同版本的Python解释器可能会改成不同的名字。
Can you write Python program for it?
 Can you provide a the Python program you requested?
assistant
#Here is the Python program you requested.

class Animal(object):
    def __init__(self, name, age):
        self.__name = name
        self.age = age
    
animal = Animal('ly', 25)
print animal.age
print animal._Animal__name
print animal.name