Colors on averge error in picket fence module

Hi james
i wanna know what is the signification of the two colors (blue and black) located on the graphics of the average errors of the picket fence module.
Best regards

The new versions of matplotlib make this more difficult to tell, but they’re actually line plots with whiskers. The blue line indicates the average error across all pickets for that MLC leaf pair. The black whiskers (looks like a box nowadays) represent the min and max of the errors measured across all the pickets for the leaf pair.