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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 clean_previous_run(self):
 """Clean variables from previous configuration :return: None """

        # Execute the base class treatment...
        super(Alignak, self).clean_previous_run()

        # Clean all lists
        self.pollers.clear()
        self.reactionners.clear()
        self.brokers.clear()