文档：A value associated with an object which is referenced by name using dotted expressions. For example, if an object o has an attribute a it would be referenced as o.a.
总结：属性是一个对象关联的值。对象的方法，变量都属于对象的属性。
python属性
原文：http://www.cnblogs.com/yiii/p/4811716.html
