docs: def is_unstructured(self, var):
          """
          Test if a variable is on an unstructered grid
  
          Parameters
          ----------
          %(CFDecoder.is_triangular.parameters)s
  
          Returns
          -------
          %(CFDecoder.is_triangular.returns)s
  
          Notes
          -----
          Currently this is the same as :meth:`is_triangular` method, but may
          change in the future to support hexagonal grids"""
          if str(var.attrs.get('grid_type')) == 'unstructured':
              return True
          xcoord = self.get_x(var)
          if xcoord is not None:
              bounds = self._get_coord_cell_node_coord(xcoord)
              if bounds is not None and bounds.shape[-1] > 2:
                  return True