docs: def get_mesh(self, var, coords=None):
          """Get the mesh variable for the given `var`
  
          Parameters
          ----------
          var: xarray.Variable
              The data source whith the ``'mesh'`` attribute
          coords: dict
              The coordinates to use. If None, the coordinates of the dataset of
              this decoder is used
  
          Returns
          -------
          xarray.Coordinate
              The mesh coordinate"""
          mesh = var.attrs.get('mesh')
          if mesh is None:
              return None
          if coords is None:
              coords = self.ds.coords
          return coords.get(mesh, self.ds.coords.get(mesh))