function addLine(selection, update) {
selection = update ? d3.select('#lines') : selection.append('g');
selection
.attr('id', 'lines')
.selectAll("path")
.data(data.byTypes.stack.data.line)
.join("path")
.style("mix-blend-mode", "multiply")
.attr('fill-opacity', 0.5)
.attr("stroke-width", 1.5)
.attr("stroke-linejoin", "round")
.attr("stroke-linecap", "round")
.attr('stroke', d => color(d.key.name))
.attr("fill", 'none')
.attr("d", line)
}