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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 start_listener(self):
        '''start listening for packets'''
        if self.sock is not None:
            self.sock.close()
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.sock.bind(('', self.asterix_settings.port))
        self.sock.setblocking(False)
        print("Started on port %u" % self.asterix_settings.port)