code: def calibrate(self, data, calibration, channel):
          
          coefs = CALIB_COEFS[self.platform_name][channel]
          is_vis = self._is_vis(channel)
  
          # IR files provide radiances, VIS file provides reflectances
          if is_vis and calibration == 'reflectance':
              return data
          elif not is_vis and calibration == 'radiance':
              return data
          elif not is_vis and calibration == 'brightness_temperature':
              return self._calibrate(radiance=data, calibration=calibration,
                                     coefs=coefs, channel=channel)
          else:
              raise ValueError('Unsupported calibration for channel {}: {}'
                               .format(channel, calibration))
docs: Perform calibration