Why doesn't isCoreLibraryDesugaringEnabled work in Gradle Kotlin DSL/KITS?

To enable desugaring in our android-library module we must put this in build.gradle:

android {
  compileOptions {
    coreLibraryDesugaringEnabled true
  }
}

But we have all scripts migrated to gradle kotlin dsl, so the problem occurs in build.gradle.kts in all three ways:

android {
    compileOptions {
        isCoreLibraryDesugaringEnabled = true
    }
}

configure<BaseExtension> {
    compileOptions {
        isCoreLibraryDesugaringEnabled = true
    }
}

android {
    if (this is com.android.build.api.dsl.LibraryExtension<*, *, *, *, *, *, *, *, *, *, *>) {
        buildFeatures.viewBinding = true
    }
}

Every time it throws

Unresolved reference: isCoreLibraryDesugaringEnabled

Does anybody have an idea how to fix this?

It wasn't working because of a missing line in the top-level build.gradle.kts. This line:

classpath("com.android.tools.build:gradle:4.0.1")