code: def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types):
          
          mean, stddevs = super().get_mean_and_stddevs(sites, rup, dists, imt,
                                                       stddev_types)
          delta = self._get_delta(imt, rup.mag)
          return mean-delta, stddevs
docs: See :meth:`superclass method
          <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
          for spec of input and result values.