def _bokeh_quants(self, inf, sup, chart_type, color):
        """
        Draw a chart to visualize quantiles
        """
        try:
            ds2 = self._duplicate_()
            qi = ds2.df[ds2.y].quantile(inf)
            qs = ds2.df[ds2.y].quantile(sup)
            ds2.add("sup", qs)
            ds2.add("inf", qi)
            ds2.chart(ds2.x, ds2.y)
            if chart_type == "point":
                c = ds2.point_(opts=self.chart_opts, style=self.chart_style)
            elif chart_type == "line_point":
                c = ds2.line_point_(opts=self.chart_opts, style=self.chart_style)
            else:
                c = ds2.line_(opts=self.chart_opts, style=self.chart_style)
            ds2.color(color)
            ds2.chart(ds2.x, "sup")
            c2 = ds2.line_()
            ds2.chart(ds2.x, "inf")
            c3 = ds2.line_()
            ds2.rcolor()
            return c * c2 * c3
        except Exception as e:
            self.err(e, "Can not draw quantile chart")
Draw a chart to visualize quantiles