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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 start(self, argv):
 """ Start BenchExec. @param argv: command-line options for BenchExec """

        parser = self.create_argument_parser()
        self.config = parser.parse_args(argv[1:])

        for arg in self.config.files:
            if not os.path.exists(arg) or not os.path.isfile(arg):
                parser.error("File {0} does not exist.".format(repr(arg)))

        if os.path.isdir(self.config.output_path):
            self.config.output_path = os.path.normpath(self.config.output_path) + os.sep

        self.setup_logging()

        self.executor = self.load_executor()

        returnCode = 0
        for arg in self.config.files:
            if self.stopped_by_interrupt:
                break
            logging.debug("Benchmark %r is started.", arg)
            rc = self.execute_benchmark(arg)
            returnCode = returnCode or rc
            logging.debug("Benchmark %r is done.", arg)

        logging.debug("I think my job is done. Have a nice day!")
        return returnCode