invoke

operator fun invoke(vararg columns: DataColumn<*>): DataFrame<*>
operator fun invoke(columns: Iterable<DataColumn<*>>): DataFrame<*>
operator fun invoke(vararg values: Any?): DataFrame<*>
operator fun invoke(args: Sequence<Any?>): DataFrame<*>
inline operator fun <reified T> invoke(crossinline valuesBuilder: (String) -> Iterable<T>): DataFrame<*>