Tooltips not working

[PMAnalytics]

Dear PBI Community,

at the moment, we are facing a problem with the PBI Tooltips.

We followed these instructions, but cant get them to work: https://docs.microsoft.com/en-us/power-bi/developer/visuals/utils-tooltip

Am I wrong, or are there some inconsistencies with the example code?

Here is our not working try on the instruction:

import "./../style/visual.less";

import powerbiVisualsApi from "powerbi-visuals-api";
import "regenerator-runtime/runtime";
import powerbi = powerbiVisualsApi;

type Selection<T1, T2 = T1> = d3.Selection<any, T1, any, T2>;

import IVisual = powerbi.extensibility.IVisual;
import IVisualHost = powerbi.extensibility.visual.IVisualHost;
import VisualUpdateOptions = powerbi.extensibility.visual.VisualUpdateOptions;
import VisualConstructorOptions = powerbi.extensibility.visual.VisualConstructorOptions;

import {createTooltipServiceWrapper, ITooltipServiceWrapper, TooltipEventArgs, TooltipEnabledDataPoint  } from "powerbi-visuals-utils-tooltiputils";


import * as d3 from "d3";


export class Visual implements IVisual {
    private tooltipServiceWrapper: ITooltipServiceWrapper;


    private host: IVisualHost;
    private svg: Selection<any>;

    
    constructor(options: VisualConstructorOptions) {

        this.host = options.host;
        this.svg = d3.select(options.element)
                .append('svg');
    }

    public update(options: VisualUpdateOptions) {
        
        this.svg.attr("width", options.viewport.width);

        this.svg.attr("height", options.viewport.height);

        this.svg
            .append("rect")
            .attr("fill", "green")
            .attr("width", "150")
            .attr("height", "150")
            .attr("x", 100)
            .attr("y", 100)
            .classed("visual", true)
            .data([{
                tooltipInfo: [{
                    displayName: "Power BI",
                    value: 2016
                }]
            }]);

        

        this.tooltipServiceWrapper = createTooltipServiceWrapper(this.host.tooltipService, this.svg.node() as Element); // tooltipService is from the IVisualHost.

        this.tooltipServiceWrapper.addTooltip(
            this.svg,
            (tooltipEvent: TooltipEventArgs<TooltipEnabledDataPoint>) => {
                return tooltipEvent.data.tooltipInfo;
            });
    }
}

Where is the problem with this code?

Thanks in advance!