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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 cycle_class(self):
 """ Return the subclass of ScfCycle associated to the task or None if no SCF algorithm if associated to the task. """

        if isinstance(self, RelaxTask):
            return abiinspect.Relaxation
        elif isinstance(self, GsTask):
            return abiinspect.GroundStateScfCycle
        elif self.is_dfpt_task:
            return abiinspect.D2DEScfCycle

        return None