1、生成MyClass类 ``` class MyClass: a = 5 b = 2 c = "hello" ``` 2、生成MyClass类，然后调用该类 ``` class MyClass: a = 5 b = 2 c = "hello" new_item = MyClass() ``` 3、生成MyClass类，然后调用该类，修改属性的值 ``` class MyClass: a = 5 b = 2 c = "hello" new_item = MyClass() print new_item.a print new_item.c new_item.a = 10 print new_item.a ```