class UrlManager(object): ? ?def __init__(self): ? ? ? ?self.new_urls = set() ? ? ? ?self.old_urls = set() ? ?def add_new_url(self, url): ? ? ? ?if url is None:? ? ? ? ? ?return ? ? ? ?if url not in self.new_urls and url not in self.old_urls: ? ? ? ? ? ?self.new_urls.add(url) ? ?def add_new_urls(self, urls): ? ? ? ?if urls is None or len(urls) == 0: ? ? ? ? ? ?return ? ? ? ?for url in urls: ? ? ? ? ? ?self.new_urls.add(url) ? ?def has_new_url(self): ? ? ? ?return len(self.new_urls) != 0 ? ?def get_new_url(self): ? ? ? ?new_url = self.new_urls.pop() ? ? ? ?self.old_urls.add(new_url) ? ? ? ?return new_url