plotGraph(data){
            let dataset = data.map(function (item) {
                let color = null;
                let value = item.percent;

                if (value > 80){
                    color = "red";
                }else{
                    color = "green";
                }
                return {"y": item.percent, "x":  new Date (item.date), "color": color
            };
                });
            let line = d3.line()
                .x(function(d, i) { return graph.xScale(d.x); }) // set the x values for the line generator
                .y(function(d) { return graph.yScale(d.y); }) // set the y values for the line generator
                .curve(d3.curveMonotoneX) // apply smoothing to the line
            const lineGenerator = d3.line()
                .x(d => x(d.date))
                .y(d => y(d.percent))
                .curve(d3.curveCardinal);

            graph.clearGraph();
            graph.svg.append("path")
                .data([dataset]) // 10. Binds data to the line
                .attr("class", "line") // Assign a class for styling
                .attr("d", line) // 11. Calls the line generator
                .attr('stroke', function(d){
                    return d.color;});
        },