def xerrorbar(self, canvas, X, Y, error, color=None, label=None, **kwargs):
        """
        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!
        """
        raise NotImplementedError("Implement all plot functions in AbstractPlottingLibrary in order to use your own plotting library")
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!