code: def _colorize_bars(self, cmap, bars, element, main_range, dim):
          
          cmap_range = main_range[1] - main_range[0]
          lower_bound = main_range[0]
          colors = np.array(element.dimension_values(dim))
          colors = (colors - lower_bound) / (cmap_range)
          for c, bar in zip(colors, bars):
              bar.set_facecolor(cmap(c))
              bar.set_clip_on(False)
docs: Use the given cmap to color the bars, applying the correct
          color ranges as necessary.