mammalsSealed.kt

sealed class Mammal(val name: String)
class Cat(val catName: String) : Mammal(catName)
class Human(val humanName: String, val job: String) : Mammal(humanName)

fun greetMammal(mammal: Mammal): String {
    return when (mammal) {
        is Human -> "Hello ${mammal.name}; You're working as a ${mammal.job}"
        is Cat -> "Hello ${mammal.name}"
    }
}