import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val numbers: List<Int?> = listOf(1, 2, null, 4)
val nonNullNumbers = mutableListOf<Int>()

println(nonNullNumbers) // []

numbers.filterNotNullTo(nonNullNumbers)

println(nonNullNumbers) // [1, 2, 4]
//sampleEnd
}