code: def check_geophysical_vars_fill_value(self, ds):
          '''
          Check that geophysical variables contain fill values.
  
          :param netCDF4.Dataset ds: An open netCDF dataset
          '''
          results = []
          for geo_var in get_geophysical_variables(ds):
              results.append(
                  self._has_var_attr(ds, geo_var, '_FillValue', '_FillValue', BaseCheck.MEDIUM),
              )
          return resultf check_geophysical_vars_fill_value(self, ds):
          '''
          Check that geophysical variables contain fill values.
  
          :param netCDF4.Dataset ds: An open netCDF dataset
          '''
          results = []
          for geo_var in get_geophysical_variables(ds):
              results.append(
                  self._has_var_attr(ds, geo_var, '_FillValue', '_FillValue', BaseCheck.MEDIUM),
              )
          return results
docs: Check that geophysical variables contain fill values.
  
          :param netCDF4.Dataset ds: An open netCDF dataset