def METHOD_NAME(self,
                        index: int,
                        parameters: Dict[str, Any]) -> xr.Dataset:
    """
    Compute the dataset at level *index*: If *index* is zero, return
    the base image passed to constructor, otherwise down-sample the
    dataset for the level at given *index*.
    :param index: the level index
    :param parameters: currently unused
    :return: the dataset for the level at *index*.
    """
    assert_instance(index, int, name='index')
    if index < 0:
        index = self.num_levels + index
    assert_true(0 <= index < self.num_levels,
                message='index out of range')
    if index == 0:
        level_dataset = self._base_dataset
    else:
        level_dataset = subsample_dataset(
            self._base_dataset,
            2 ** index,
            xy_dim_names=self.grid_mapping.xy_dim_names,
            agg_methods=self._agg_methods
        )
    # Tile each level according to grid mapping
    tile_size = self.grid_mapping.tile_size
    if tile_size is not None:
        level_dataset, _ = rechunk_cube(level_dataset,
                                        self.grid_mapping,
                                        tile_size=tile_size)
    return level_dataset