swift – HighCharts(iOS) -The right way to present tooltip by default at just some positions

HighCharts(iOS): The right way to present tooltip by default at just some positions by passing the index in swift, discovered the under instance in javascript

let chart = Highcharts.chart('container', {
  chart: {
    occasions: {
      load() {
        this.tooltip.refresh(this.collection[0].factors[2]);
        this.tooltip.refresh(this.collection[0].factors[4]);
      }
    }
  },
  tooltip: {
    formatter: perform() {
      return '3';
    }
  },

tried one thing like this

chart.occasions.load = tooltip.refresh(by: tooltipFunction)

can anybody convert the javascript to swift(iOS)

demo in javascript

https://jsfiddle.internet/BlackLabel/mqz3Ljy6/