code: def _calibrate(self, data):
          
          idx = self.mda['calibration_parameters']['indices']
          val = self.mda['calibration_parameters']['values']
          data.data = da.where(data.data == 0, np.nan, data.data)
          ddata = data.data.map_blocks(np.interp, idx, val, dtype=val.dtype)
          res = xr.DataArray(ddata,
                             dims=data.dims, attrs=data.attrs,
                             coords=data.coords)
          res = res.clip(min=0)
          units = {'percent': '%'}
          unit = self.mda['calibration_parameters'][b'_UNIT']
          res.attrs['units'] = units.get(unit, unit)
          return res
docs: Calibrate *data*.