Pythonn new-style class and old-style class

In [1]: class old():
   ...:     a = 1
   ...:     

In [2]: o = old()

In [3]: o.__class__
Out[3]: <class __main__.old at 0x7fb1fd1c56d0>

In [4]: type(o)
Out[4]: instance

In [5]: class new(object):
   ...:     a = 2
   ...:     

In [6]: n = new()

In [7]: n.__class__
Out[7]: __main__.new

In [8]: type(n)
Out[8]: __main__.new

1）在多继承中，新式类采用广度优先搜索，而旧式类是采用深度优先搜索。

2）新式类更符合OOP编程思想，统一了python中的类型机制。

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