x = [10,20,30,40,50,60]
p = plot(None,name="Data 1")[0]
p.addSeries(LinePlotSeries("Data2"))
p.getSeries(0).setData(x, [1,2,3,4,5,6])    
p.getSeries(1).setData(x, [6,5,4,3,2,1])    
p.addMarker(35.0, None, "This is the answer", None)