change y to ids and checks

    """Gets size of shards on disk."""

    if not len(self.metadata_df):

      raise ValueError("No data in dataset.")

    sample_y = load_from_disk(

    sample_ids = load_from_disk(

        os.path.join(self.data_dir,

                     next(self.metadata_df.iterrows())[1]['y']))

    return len(sample_y)

                     next(self.metadata_df.iterrows())[1]['ids']))

    return len(sample_ids)

  def _get_metadata_filename(self) -> Tuple[str, str]:

    """Get standard location for metadata file."""

          if y is not None:

            y_sel = y[shard_inds]

          else:

            y_sel = None

            y_sel = np.array([])

          if w is not None:

            w_sel = w[shard_inds]

          else:

            w_sel = None

            w_sel = np.array([])

          ids_sel = ids[shard_inds]

          Xs.append(X_sel)

          ys.append(y_sel)

                np.where(sorted_indices == orig_index)[0][0]

                for orig_index in select_shard_indices

            ])

        X, y, w, ids = X[reverted_indices], y[reverted_indices], w[

            reverted_indices], ids[reverted_indices]

        yield (X, y, w, ids)

        if y.size == 0:

          tup_y = y

        else:

          tup_y = y[reverted_indices]

        if w.size == 0:

          tup_w = w

        else:

          tup_w = w[reverted_indices]

        X, ids = X[reverted_indices], ids[reverted_indices]

        yield (X, tup_y, tup_w, ids)

        start = end

        select_shard_num += 1