class TheThing(object):     #类的声明，object不能省略

    def __init__(self):     #这里是in it的意思，即设置内部变量
        self.number = 0

    def some_function(self): #class中的固定的参数，实现变量x.函数名y(self)的用法中函数的参数即为x
        print ("I got called.")

    def add_me_up(self, more):
        self.number += more
        return self.number

# two different things
a = TheThing() #定义变量a为TheTHhing类，下同
b = TheThing()

a.some_function() #对a调用TheThing类里的some_function函数，下同
b.some_function()

print (a.add_me_up(20) )#对a调用Thething类里的add_me_up函数，下同
print (a.add_me_up(20))
print (b.add_me_up(30))
print (b.add_me_up(30))

print (a.number) #打印当前a.number的值，由于类中self.number=0，所以定义a为TheThing类时，该值为零
print (b.number)