暂时在工作中，还没有用到呢~~~
以后要留意一下，主要用于复制对象副本，
然后又有自定义属性的地方。
import copy from collections import OrderedDictclass Book:def __init__(self, name, authors, price, **rest):self.name = nameself.authors = authorsself.price = priceself.__dict__.update(rest)def __str__(self):mylist = []ordered = OrderedDict(sorted(self.__dict__.items()))for i in ordered.keys():mylist.append('{}: {}'.format(i, ordered[i]))if i == 'price':mylist.append('$')mylist.append('\n')return ''.join(mylist)class Prototype:def __init__(self):self.objects = dict()def register(self, identifier, obj):self.objects[identifier] = objdef unregister(self, identifier):del self.objects[identifier]def clone(self, identifier, **attr):found = self.objects.get(identifier)if not found:raise ValueError('Incorrect object identifier: {}'.format(identifier))obj = copy.deepcopy(found)obj.__dict__.update(attr)return objdef main():b1 = Book('The C Programming Language', ('Brian W. Kernighan', 'Dennis M. Ritchie'),price=118, publisher='Prentice Hall', length=228, publication_date='1978-02-22',tags=('C', 'programming', 'algorithms', 'data stuctures'))prototype = Prototype()cid = 'k&r-first'prototype.register(cid, b1)b2 = prototype.clone(cid, name='The C Programming Language(ANSI', price=48.99,publisher='Prentice Hall', length=274, publication_date='1988-05-01', edition=2)for i in (b1, b2):print(i)print("ID b1 : {} != ID b2 : {}".format(id(b1), id(b2)))if __name__ == '__main__':main()
