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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_intensity_measure_types(self):
 """ If the IMTs and levels are extracted from the risk models, they must not be set directly. Moreover, if `intensity_measure_types_and_levels` is set directly, `intensity_measure_types` must not be set. """

        if self.ground_motion_correlation_model:
            for imt in self.imtls:
                if not (imt.startswith('SA') or imt == 'PGA'):
                    raise ValueError(
                        'Correlation model %s does not accept IMT=%s' % (
                            self.ground_motion_correlation_model, imt))
        if self.risk_files:  # IMTLs extracted from the risk files
            return (self.intensity_measure_types is None and
                    self.intensity_measure_types_and_levels is None)
        elif not hasattr(self, 'hazard_imtls') and not hasattr(
                self, 'risk_imtls'):
            return False
        return True