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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 update_file(self, fullpath):
 """ Update a file """

        if SCHEDULED_FILES.add(fullpath):
            logger.debug("Scheduling reindex of %s", fullpath)
            relpath = os.path.relpath(fullpath, self.content_dir)
            THREAD_POOL.submit(scan_file, fullpath, relpath, False)