docs: function ChartGrid () {
      var gridLinker = function (scope, element, attrs, chartCtrl) {
          var showX = attrs.showX;
          if (showX && showX === "true") {
              chartCtrl.addGrid("x");
          }
          var showY = attrs.showY;
          if (showY && showY === "true") {
              chartCtrl.addGrid("y");
          }
          var showY2 = attrs.showY2;
          if (showY2 && showY2 === "true") {
              chartCtrl.addGrid("y2");
          }
          var showFocus = attrs.showFocus;
          if (showFocus && showFocus === "false") {
              chartCtrl.hideGridFocus();
          }
      };
  
      return {
          "require": "^c3chart",
          "restrict": "E",
          "scope": {},
          "replace": true,
          "link": gridLinker,
          "transclude": true,
          "template": "<div ng-transclude></div>"
      };
  }