code: function (options, isX, redraw, animation) {
  		var key = isX ? 'xAxis' : 'yAxis',
  			chartOptions = this.options,
  			axis;
  
  		/*jslint unused: false*/
  		axis = new Axis(this, merge(options, {
  			index: this[key].length,
  			isX: isX
  		}));
  		/*jslint unused: true*/
  
  		// Push the new axis options to the chart options
  		chartOptions[key] = splat(chartOptions[key] || {});
  		chartOptions[key].push(options);
  
  		if (pick(redraw, true)) {
  			this.redraw(animation);
  		}
  	}
docs: Add an axis to the chart
  @param {Object} options The axis option
  @param {Boolean} isX Whether it is an X axis or a value axis