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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):
 """Cleanup client resources and disconnect from MongoDB. On MongoDB >= 3.6, end all server sessions created by this client by sending one or more endSessions commands. Close all sockets in the connection pools and stop the monitor threads. If this instance is used again it will be automatically re-opened and the threads restarted. .. versionchanged:: 3.6 End all server sessions created by this client. """

        session_ids = self._topology.pop_all_sessions()
        if session_ids:
            self._end_sessions(session_ids)
        # Stop the periodic task thread and then run _process_periodic_tasks
        # to send pending killCursor requests before closing the topology.
        self._kill_cursors_executor.close()
        self._process_periodic_tasks()
        self._topology.close()