docs: def _combine(self, applied, shortcut=False):
          """Recombine the applied objects like the original."""
          applied_example, applied = peek_at(applied)
          coord, dim, positions = self._infer_concat_args(applied_example)
          if shortcut:
              combined = self._concat_shortcut(applied, dim, positions)
          else:
              combined = concat(applied, dim)
              combined = _maybe_reorder(combined, dim, positions)
  
          if isinstance(combined, type(self._obj)):
              # only restore dimension order for arrays
              combined = self._restore_dim_order(combined)
          if coord is not None:
              if shortcut:
                  combined._coords[coord.name] = as_variable(coord)
              else:
                  combined.coords[coord.name] = coord
          combined = self._maybe_restore_empty_groups(combined)
          combined = self._maybe_unstack(combined)
          return combined