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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 is_valid_optimize_same_id_sources(self):
 """ The `optimize_same_id_sources` can be true only in the classical calculators. """

        if (self.optimize_same_id_sources and
                'classical' in self.calculation_mode or
                'disagg' in self.calculation_mode):
            return True
        elif self.optimize_same_id_sources:
            return False
        else:
            return True