code: function buildContainerGroups(){
              let container = svg
                .append('g')
                  .classed('container-group', true)
                  .attr('transform', `translate(${margin.left},${margin.top})`);
  
              container
                .append('g').classed('x-axis-group', true)
                .append('g').classed('axis x', true);
              container.selectAll('.x-axis-group')
                .append('g').classed('month-axis', true);
              container
                .append('g').classed('y-axis-group', true)
                .append('g').classed('axis y', true);
              container
                .append('g').classed('grid-lines-group', true);
              container
                .append('g').classed('chart-group', true);
              container
                .append('g').classed('metadata-group', true);
          }
docs: Builds containers for the chart, the axis and a wrapper for all of them
  NOTE: The order of drawing of this group elements is really important,
  as everything else will be drawn on top of them
  @private