code: def getcal(self):
          
  
          status, cal, cal_error, offset, offset_err, data_type = \
                           _C.SDgetcal(self._id)
          _checkErr('getcal', status, 'no calibration record')
          return cal, cal_error, offset, offset_err, data_type
docs: Retrieve the SDS calibration coefficients.
  
          Args::
  
            no argument
  
          Returns::
  
            5-element tuple holding:
  
            - cal: calibration factor (attribute 'scale_factor')
            - cal_error : calibration factor error
                          (attribute 'scale_factor_err')
            - offset: calibration offset (attribute 'add_offset')
            - offset_err : offset error (attribute 'add_offset_err')
            - data_type : type of the data resulting from applying
                          the calibration formula to the dataset values
                          (attribute 'calibrated_nt')
  
          An exception is raised if no calibration data are defined.
  
          Original dataset values 'orival' are converted to calibrated
          values 'calval' through the formula::
  
             calval = cal * (orival - offset)
  
          The calibration coefficients are part of the so-called
          "standard" SDS attributes. The values inside the tuple returned
          by 'getcal' are those of the following attributes, in order::
  
            scale_factor, scale_factor_err, add_offset, add_offset_err,
            calibrated_nt
  
          C library equivalent: SDgetcal()