vl.markLine()
.encode(
vl.x().fieldO("WEEK").title(null),
vl.y().sum("INCIDENCE").title("Incidentie per week"),
vl.color().field("AGEGROUP").scale({scheme: "turbo"}).title("Leeftijd")
)
.height(200)
.data(age_cases.filter(d => d.WEEK < 2021.37).filter(d => d.WEEK >= 2021.15))
.render();