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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 close(self):
 """Ends the background threads, and prevent this instance from servicing further queries."""

        if globals()['_GLOBAL_DONE'] == 0:
            globals()['_GLOBAL_DONE'] = 1
            self.notify_all()
            self.engine.notify()
            self.unregister_all_services()
            for i in self.intf.values():
                try:
                    # there are cases, when we start mDNS without network
                    i.setsockopt(socket.SOL_IP, socket.IP_DROP_MEMBERSHIP,
                            socket.inet_aton(_MDNS_ADDR) + \
                                    socket.inet_aton('0.0.0.0'))
                except:
                    pass
                i.close()