Example2.Solution.kt

class Preferences {
    fun getPreferenceState(key: String): StateFlow<PreferenceState>  { ... }

    fun getMultiplePreferenceState(keys: List<String>): StateFlow<MultiplePreferenceState> {
        val prefStateFlows = keys.map { getPreferenceState(it) }.toTypedArray()

        return combineStates(*prefStateFlows) { prefStates: Array<PreferenceState> ->
            MultiplePreferenceState(prefStates.toList())
        }
    }
}