docs: def draw(self, y, **kwargs):
          """
          Draws a histogram with the reference value for binning as vertical
          lines.
  
          Parameters
          ----------
          y : an array of one dimension or a pandas Series
          """
  
          # draw the histogram
          hist, bin_edges = np.histogram(y, bins=self.bins)
          self.bin_edges_ = bin_edges
          self.ax.hist(y, bins=self.bins, color=kwargs.pop("color", "#6897bb"), **kwargs)
  
          # add vetical line with binning reference values
          plt.vlines(bin_edges,0,max(hist),colors=kwargs.pop("colors", "r"))