https://proandroiddev.com/one-liner-intent-bundle-extras-extractor-in-kotlin-f4b614b390c4

MyActivity.kt

const val ID = "id"

class MyActivity : Activity() {

    private val id1 by extra<String>(ID) // String?
    private val id2 by extraNotNull<String>(ID) // String

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        requireNotNull(id1, id2)
    }

}