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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):
 """Start the background emulation loop."""


        if self._started is True:
            raise ArgumentError("EmulationLoop.start() called multiple times")

        self._thread = threading.Thread(target=self._loop_thread_main)
        self._thread.start()
        self._started = True