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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_loop=True):
 """Start all the things. :param start_loop bool: whether to start the ioloop. should be False if the IOLoop is managed externally """

        self.start_alerts()
        if self.options.get('pidfile'):
            with open(self.options.get('pidfile'), 'w') as fpid:
                fpid.write(str(os.getpid()))
        self.callback.start()
        LOGGER.info('Reactor starts')

        if start_loop:
            self.loop.start()