def METHOD_NAME(self, vars):
    from fipy.meshes.uniformGrid2D import UniformGrid2D
    from fipy.variables.cellVariable import CellVariable
    vars = [var for var in AbstractMatplotlib2DViewer.METHOD_NAME(self, vars) \
      if (isinstance(var.mesh, UniformGrid2D) and isinstance(var, CellVariable)
          and var.rank == 0)]
    if len(vars) == 0:
        from fipy.viewers import MeshDimensionError
        raise MeshDimensionError("Matplotlib2DGridViewer can only display a rank-0 CellVariable with a UniformGrid2D mesh")
    # this viewer can only display one variable
    return [vars[0]]