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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 _shutdown_listen_socket(self):
 """ Shutdown listening socket :rtype: None """

        self.debug("()")
        if self._listen_socket in self._listening:
            self._listening.remove(self._listen_socket)
        if self._listen_socket:
            self._listen_socket.close()
        self._listen_socket = None