| The new class | Old class |
|---|---|
| Breadth-First | Depth-first |
| Python 3.x default are the new class (object can not write) | Python 2.x default is classic class, only inherited the object is explicitly new class |
| Method new class built __new__ | Classic not only __new__ method __init__ method |
| __new__ method prior to __init__ method is called in the instance creation process, it's the first argument of type type. |
