code: def set_parameter_scale(self, name, par, scale):
          
          name = self.roi.get_source_by_name(name).name
          idx = self.like.par_index(name, par)
          current_bounds = list(self.like.model[idx].getBounds())
          current_scale = self.like.model[idx].getScale()
          current_value = self.like[idx].getValue()
  
          self.like[idx].setScale(scale)
          self.like[idx].setValue(current_value * current_scale / scale)
          self.like[idx].setBounds(current_bounds[0] * current_scale / scale,
                                   current_bounds[1] * current_scale / scale)
          self._sync_params(name)
docs: Update the scale of a parameter while keeping its value constant.