docs: function (out) {
              var cfg = this._cfg;
              var tabString = (cfg.tabIndex != null ? ' tabindex="' + this._calculateTabIndex() + '" ' : ' ');
              out.write(['<a', Aria.testMode ? ' id="' + this._domId + '_link"' : '',
                      ' class="sortIndicatorLink" href="#"' + tabString + this._getWaiAriaMarkup() + '>' + ariaUtilsString.escapeHTML(cfg.label)].join(""));
              this._icon.writeMarkup(out);
              out.write('</a>');
          }