docs: def draw_stacked_bar(self, nan_col_counts):
          """Draws a horizontal stacked bar chart with different colors
          for each count of nan values per label.
          """
          for index, nan_values in enumerate(nan_col_counts):
              label, nan_col_counts = nan_values
  
              if index == 0:
                  # first draw should be at zero
                  bottom_chart = np.zeros(nan_col_counts.shape)
  
              # if features passed in then, label as such
              if self.classes_ is not None:
                  label = self.classes_[index]
  
              color = self.colors[index]
  
              self.ax.barh(self.ind - self.width / 2, nan_col_counts, self.width,
                          color=color, label=label, left=bottom_chart)
  
              # keep track of counts to build on stacked
              bottom_chart = nan_col_counts