How to save a function reference as the value in a Map type, and invoke it with a parameter later on in Kotlin?

val specials:Map<String, (Any)->Unit> = mapOf(
        "callMe1" to {asParam1()}, 
        "callMe2" to {asParam2()}
)

fun asParam1(num:Int) {
    println(num)
}

fun asParam2(text:String) {
    println(text)
}

fun caller() {
    specials["callMe1"]?.invoke("print me")
    specials["callMe2"]?.invoke(123)
}


fun main(args: Array<String>) {
    caller()
}

My requirement is simple, I want to save the function asParam1 and asParam2 as a value in the variable specials. And invoke it later on by fetching the value from a Map.

However, the compiler doesn't like it:

Error:(1, 40) Type inference failed. Expected type mismatch: inferred type is Map Unit> but Map Unit> was expected
Error:(1, 69) No value passed for parameter num
Error:(1, 96) No value passed for parameter text

While this task is pretty simple in a weak typed language, I don't know how to do in Kotlin. Any help would be welcome. Thanks!