http://blog.csdn.net/tangsilian/article/details/51517392
2016-05-27
已采纳回答 / SunCherryDream
需要定义构造函数与,在构造函数中对new_urls进行初始化,构造函数代码如下def __init__(self): self.new_urls = set() self.old_urls = set()
2016-05-23