For medium article: https://medium.com/@amatkivskiy/legacy-code-pitfalls-35feda5acb71

nested-fix.kt

val child = parentObj.child?.child?.child
if (child != null) {
    doSomethingOnBooleanValue(child.isValid)
} else {
    // handle null value here
}

fun doSomethingOnBooleanValue(valid: Boolean) {
    if (valid) {
        // `valid` is really true
    } else {
        // `valid` is false
    }
}