How to use gradient

[dariogriffo]

Trying to reproduce this code

plotOptions: { series: { fillColor: { linearGradient: [0, 0, 0, 300], stops: [ [0, Highcharts.getOptions().colors[0]], [1, Highcharts.Color(Highcharts.getOptions().colors[0]).setOpacity(0).get('rgba')] ] } } }

I can't fine the Highcharts.Color function. Any hint on how to create an area chart with gradient colors like https://jsfiddle.net/gh/get/library/pure/highcharts/highcharts/tree/master/samples/highcharts/plotoptions/area-fillcolor-gradient/