code: def xerrorbar(self, canvas, X, Y, error, color=None, label=None, **kwargs):
          
          raise NotImplementedError("Implement all plot functions in AbstractPlottingLibrary in order to use your own plotting library")
docs: Make an errorbar along the xaxis for points at (X,Y) on the canvas.
          if error is two dimensional, the lower error is error[:,0] and
          the upper error is error[:,1]
          
          the kwargs are plotting library specific kwargs!