如何通过__dict__分配新的类属性？

这有一个内置函数:

setattr(test, attr_name, 10)

参考:http://docs.python.org/library/functions.html#setattr

例:

>>> class a(object): pass
>>> a.__dict__['wut'] = 4
Traceback (most recent call last):
  File "", line 1, in 
TypeError: 'dictproxy' object does not support item assignment
>>> setattr(a, 'wut', 7)
>>> a.wut
7