docs: def _combine(self, applied):
          """Recombine the applied objects like the original."""
          applied_example, applied = peek_at(applied)
          coord, dim, positions = self._infer_concat_args(applied_example)
          combined = concat(applied, dim)
          combined = _maybe_reorder(combined, dim, positions)
          if coord is not None:
              combined[coord.name] = coord
          combined = self._maybe_restore_empty_groups(combined)
          combined = self._maybe_unstack(combined)
          return combined