code: def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types):
          
          # extract dictionaries of coefficients specific to required
          # intensity measure type
          C = self.COEFFS[imt]
          imean = (self._get_magnitude_scaling_term(C, rup.mag) +
                   self._get_distance_scaling_term(C, dists.rjb, rup.mag))
          # convert from cm/s**2 to g for SA and from cm/s**2 to g for PGA (PGV
          # is already in cm/s) and also convert from base 10 to base e.
          if imt.name in "SA PGA":
              mean = np.log((10.0 ** (imean - 2.0)) / g)
          else:
              mean = np.log(10 ** imean)
  
          stddevs = self._get_stddevs(C, stddev_types, dists.rjb.shape[0])
  
          return mean, stddevs
docs: See :meth:`superclass method
          <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
          for spec of input and result values.