code: function drawAxis(){
              svg.select('.x-axis-group.axis')
                  .attr('transform', `translate(0, ${chartHeight})`)
                  .call(xAxis);
  
              svg.selectAll('.x-axis-group .tick text')
                  .style('text-anchor', 'start')
                  .attr('transform', 'rotate(45 -1 10)');
  
              if (xAxisLabel) {
                  if (xAxisLabelEl) {
                      svg.selectAll('.x-axis-label-text').remove();
                  }
                  xAxisLabelEl = svg.select('.x-axis-label')
                    .append('text')
                      .attr('y', xAxisLabelOffset)
                      .attr('text-anchor', 'middle')
                      .classed('x-axis-label-text', true)
                      .attr('x', chartWidth / 2)
                      .text(xAxisLabel);
              }
  
              svg.select('.y-axis-group.axis')
                  .call(yAxis);
  
              if (yAxisLabel) {
                  if (yAxisLabelEl) {
                      svg.selectAll('.y-axis-label-text').remove();
                  }
                  yAxisLabelEl = svg.select('.y-axis-label')
                    .append('text')
                      .classed('y-axis-label-text', true)
                      .attr('x', -chartHeight / 2)
                      .attr('y', yAxisLabelOffset)
                      .attr('text-anchor', 'middle')
                      .attr('transform', 'rotate(270 0 0)')
                      .text(yAxisLabel);
              }
          }
docs: Draws the x and y axis on the svg object within their
  respective groups
  @private