code: function drawHourLabels() {
              let hourLabelsGroup = svg.select('.hour-labels-group');
  
              hourLabels = svg.select('.hour-labels-group').selectAll('.hour-label')
                  .data(hoursHuman);
  
              hourLabels.enter()
                .append('text')
                  .text((label) => label)
                  .attr('y', 0)
                  .attr('x', (d, i) => i * boxSize)
                  .style('text-anchor', 'middle')
                  .style('dominant-baseline', 'central')
                  .attr('class', 'hour-label');
  
              hourLabelsGroup.attr('transform', `translate(${boxSize / 2}, -${hourLabelHeight})`);
          }
docs: Draws the hour labels