Staked bar label


in a bar chart, I have two categories, but when i activate ‘Labels?’ the labels do not look good and I want to hide the label of one of the two categories

the following code does it well for me, but after a while the label reappears

if event.propertyName=='data':
 from java.awt import Color
 plot = event.source.getChart().getPlot()
 renderer = plot.getRenderer()
 renderer.setSeriesItemLabelPaint(1, Color(0,0,0,0))

thanks you