Python 任意数量的关键字实参

将函数编写成能够接受任意数量的键-值对——调用语句提供类多少就接受多少，直接看下面例子：

>>> def build_profile(first,last,**user_info):
...     profile = {}
...     profile['first_name'] = first
...     profile['last_name'] = last
...     for key,value in user_info.items():
...             profile[key] = value
...     return profile
... 
>>> user_profile = build_profile('albert','einstein',location='princeton',field='physics')
>>> print(user_profile)
{'last_name': 'einstein', 'location': 'princeton', 'first_name': 'albert', 'field': 'physics'}