code: function drawGroupedBar() {
              // Not ideal, we need to figure out how to call exit for nested elements
              if (layerElements) {
                  svg.selectAll('.layer').remove();
              }
  
              let series = svg.select('.chart-group').selectAll('.layer');
  
              animationDelays = d3Array.range(animationDelayStep, (layers.length + 1) * animationDelayStep, animationDelayStep)
              if (isHorizontal) {
                  drawHorizontalBars(series);
              } else {
                  drawVerticalBars(series);
              }
  
              // Exit
              series.exit()
                  .transition()
                  .style('opacity', 0)
                  .remove();
          }
docs: Draws the different areas into the chart-group element
  @private