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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 unset_impact_state(self):
 """Unset impact, only if impact state change is set in configuration :return: None """

        cls = self.__class__
        if cls.enable_problem_impacts_states_change and not self.state_changed_since_impact:
            self.state = self.state_before_impact
            self.state_id = self.state_id_before_impact