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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 _job_sorting_key(self, job):
 """ Get the sorting key of a CFGJob instance. :param CFGJob job: the CFGJob object. :return: An integer that determines the order of this job in the queue. :rtype: int """


        if self._base_graph is None:
            # we don't do sorting if there is no base_graph
            return 0

        MAX_JOBS = 1000000

        if job.addr not in self._node_addr_visiting_order:
            return MAX_JOBS

        return self._node_addr_visiting_order.index(job.addr)