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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def mark_good(self, proxy):
 """ Mark a proxy as good """

        if proxy not in self.proxies:
            logger.warn("Proxy <%s> was not found in proxies list" % proxy)
            return

        if proxy not in self.good:
            logger.debug("Proxy <%s> is GOOD" % proxy)

        self.unchecked.discard(proxy)
        self.dead.discard(proxy)
        self.good.add(proxy)
        self.proxies[proxy].failed_attempts = 0