def draw_letter_value_plot(self, ax, kws):
        vert = self.orient == "v"

        for i, group_data in enumerate(self.plot_data):

            if self.plot_hues is None:

                # Handle case where there is data at this level
                if group_data.size == 0:
                    continue

                # Draw a single box or a set of boxes
                # with a single level of grouping
                box_data = remove_na(group_data)

                # Handle case where there is no non-null data
                if box_data.size == 0:
                    continue

                color = self.colors[i]

                artist_dict = self._lvplot(box_data,
                                           positions=[i],
                                           color=color,
                                           vert=vert,
                                           widths=self.width,
                                           k_depth=self.k_depth,
                                           ax=ax,
                                           scale=self.scale,
                                           outlier_prop=self.outlier_prop,
                                           **kws)

            else:
                # Draw nested groups of boxes
                offsets = self.hue_offsets
                for j, hue_level in enumerate(self.hue_names):

                    # Add a legend for this hue level
                    if not i:
                        self.add_legend_data(ax, self.colors[j], hue_level)

                    # Handle case where there is data at this level
                    if group_data.size == 0:
                        continue

                    hue_mask = self.plot_hues[i] == hue_level
                    box_data = remove_na(group_data[hue_mask])

                    # Handle case where there is no non-null data
                    if box_data.size == 0:
                        continue

                    color = self.colors[j]
                    center = i + offsets[j]
                    artist_dict = self._lvplot(box_data,
                                               positions=[center],
                                               color=color,
                                               vert=vert,
                                               widths=self.nested_width,
                                               k_depth=self.k_depth,
                                               ax=ax,
                                               scale=self.scale,
                                               outlier_prop=self.outlier_prop,
                                               **kws)
Use matplotlib to draw a letter value plot on an Axes.
dataset/ETHPy150Open mwaskom/seaborn/seaborn/categorical.py/_LVPlotter.draw_letter_value_plot