docs: def calibrate(filename):
      """
      Append the calibration parameters as variables of the netcdf file.
  
      Keyword arguments:
      filename -- the name of a netcdf file.
      """
      params = calibration_to(filename)
      with nc.loader(filename) as root:
          for key, value in params.items():
              nc.getdim(root, 'xc_1', 1)
              nc.getdim(root, 'yc_1', 1)
              if isinstance(value, list):
                  for i in range(len(value)):
                      nc.getvar(root, '%s_%i' % (key, i), 'f4', ('time', 'yc_1', 'xc_1' ))[:] = value[i]
              else:
                  nc.getvar(root, key, 'f4', ('time', 'yc_1', 'xc_1'))[:] = value