functions simply pass through to ternary's functions with the same names. This class manages the matplotlib axes, the scale, and the boundary scale to ease the use of ternary plotting functions.
Since matplotlib 2.2.0 the API has changed: The Axes.get_axis_bgcolor, Axes.set_axis_bgcolor, Bbox.update_from_data, box.update_datalim_numerix, MaxNLocator.bin_boundaries methods have been removed.