Chaining Kotlin Type Casting and following execution together!! (1)

after.kt

// add this !!
infix fun <T, R> T?.then(block: T.() -> R): R? = this?.block()

abstract class Animal

class Cat : Animal() {
    fun say() = "meow"
}

fun main() {
    val myCat: Animal = Cat()
    myCat as? Cat then { println(say()) }
}