citiesDataRestructured = citiesDataCleaned.clone().mergeItems({
dataToBeMerged: citiesInfoRaw,
commonkey:"id"
})
.addkey({
key:"year",
itemGenerator: (item) => item.date.getFullYear() })
.addKey({
key: "decade",
itemGenerator: (item) => Math.floor(item.year / 10) * 10
})