code: function(e, legendItem) {
  			var index = legendItem.datasetIndex;
  			var ci = this.chart;
  			var meta = ci.getDatasetMeta(index);
  
  			// See controller.isDatasetVisible comment
  			meta.hidden = meta.hidden === null ? !ci.data.datasets[index].hidden : null;
  
  			// We hid a dataset ... rerender the chart
  			ci.update();
  		}
docs: a callback that will handle