sortByImpl

internal fun <T, G> GroupBy<T, G>.sortByImpl(columns: SortColumnsSelector<G, *>): GroupBy<T, G>
internal fun <T, C> DataFrame<T>.sortByImpl(unresolvedColumnsPolicy: UnresolvedColumnsPolicy = UnresolvedColumnsPolicy.Fail, columns: SortColumnsSelector<T, C>): DataFrame<T>