split

fun <T> DataFrame<T>.split(vararg columns: String): Split<T, Any>

fun <T, C> DataFrame<T>.~~split~~(vararg columns: ColumnReference<C?>): Split<T, C>

fun <T, C> DataFrame<T>.~~split~~(vararg columns: KProperty<C?>): Split<T, C>

It's recommended to migrate to the String or Extension Properties Access API https://kotlin.github.io/dataframe/apilevels.html