code: function() {
  
              var self = this;
  
              if(this.options.insightsPanelBuilder) {
                  // use the customize insights panel builder
                  return self.options.insightsPanelBuilder(self);
              } else {
                  // using the default search box.
                  return self.defaultInsightsPanel(self);
              }
          }
docs: ================================================================= handle the insights panel builder and feeder. ================================================================= 
  build the insights panel.