// WITH_RUNTIME
// INTENTION_TEXT: "Replace with 'flatMap{}.firstOrNull{}'"
// INTENTION_TEXT_2: "Replace with 'asSequence().flatMap{}.firstOrNull{}'"
fun foo(list: List<String>): String? {
    <caret>return list
        .flatMap { it.lines() }
        .firstOrNull { !it.isBlank() }
}