python **kwargs

>>> class tree:
...     def __init__(self, value, **kwargs):
...             exec "self.%s = kwargs" % value
...
>>> t = tree('x', k='v')
>>> print t
<__main__.tree instance at 0xb7ec464c>
>>> print t.x
{'k': 'v'}
>>> t = tree('x', **{'k' : 'v'})
>>> print t.x
{'k': 'v'}
>>> print **{'a' : 1, 'b' : 2}
  File "", line 1
    print **{'a' : 1, 'b' : 2}
           ^
SyntaxError: invalid syntax

参考：
2007/05/python-datetime-object-from.html