<@U0Q2YA9BK> No, `groupBy` returns a map and `mapV...

# getting-started

[karelpeeters]

@dierre No, groupBy returns a map and mapValues operates on the entries of that map.
See https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/group-by.html and https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/map-values.html.