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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 _mark_in_progress(self, node_id):
 """Mark the node as 'in progress'. Callers must hold the lock. :param str node_id: The node ID to mark as in progress. """

        self.queued.remove(node_id)
        self.in_progress.add(node_id)