) {
    public fun create(providers: List<P>): P = when (providers.size) {
        0 -> emptyProvider
        1 -> providers.single()
        else -> composeProviders(providers)
    }

    public fun createFlattened(providers: List<P>): P =
        create(if (providers.size > 1) flatten(providers) else providers)

    public fun flatten(providers: List<P>): List<P> =
        providers.flatMap { provider ->