code: function (titleOptions, subtitleOptions, redraw) {
              var chart = this,
                options = chart.options,
                chartTitleOptions,
                chartSubtitleOptions;
  
              chartTitleOptions = options.title = merge(options.title, titleOptions);
              chartSubtitleOptions = options.subtitle = merge(options.subtitle, subtitleOptions);
  
              // add title and subtitle
              each([
                  ['title', titleOptions, chartTitleOptions],
                  ['subtitle', subtitleOptions, chartSubtitleOptions]
              ], function (arr) {
                  var name = arr[0],
                    title = chart[name],
                    titleOptions = arr[1],
                    chartTitleOptions = arr[2];
  
                  if (title && titleOptions) {
                      chart[name] = title = title.destroy(); // remove old
                  }
  
                  if (chartTitleOptions && chartTitleOptions.text && !title) {
                      chart[name] = chart.renderer.text(
                        chartTitleOptions.text,
                        0,
                        0,
                        chartTitleOptions.useHTML
                        )
                        .attr({
                            align: chartTitleOptions.align,
                            'class': PREFIX + name,
                            zIndex: chartTitleOptions.zIndex || 4
                        })
                        .css(chartTitleOptions.style)
                        .add();
                  }
              });
              chart.layOutTitles(redraw);
          }
docs: Show the title and subtitle of the chart
  
  @param titleOptions {Object} New title options
  @param subtitleOptions {Object} New subtitle options