def contour(self, canvas, X, Y, C, Z=None, color=None, label=None, **kwargs):
raise NotImplementedError("<STR_LIT>")<EOL>
Make a contour plot at (X, Y) with heights/colors stored in C on the canvas.

if Z is not None: make 3d contour plot at (X, Y, Z) with heights/colors stored in C on the canvas.

the kwargs are plotting library specific kwargs!