class proxy_iter:
    def __init__(self,proxies):
        self._proxies = set(proxies)
        self.proxies = self._proxies.copy()
        self.bad_proxies = set()
        # self.used_proxies = {}
        
    def __next__(self):
        self.proxies -= self.bad_proxies
        if len(self.proxies) == 0:
            raise StopIteration

        elem = self.proxies.pop()
        if len(self.proxies) == 0:
            self.proxies = self._proxies.copy()
        return elem
        
    def __iter__(self):
        return self
    def blacklist(self,proxy):
        self.bad_proxies.add(proxy)