def METHOD_NAME(self, vars):
    from fipy.meshes.nonUniformGrid2D import NonUniformGrid2D
    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, NonUniformGrid2D)
           or isinstance(var.mesh, UniformGrid2D))
          and isinstance(var, CellVariable))]
    if len(vars) == 0:
        from fipy.viewers import MeshDimensionError
        raise MeshDimensionError("The mesh must be a Grid2D instance")
    # this viewer can only display one variable
    return [vars[0]]