how to use default parameter in retrofit GET Request with method reference expression(double colon expression)

Question

now i refactoring my codes. and i try to use method reference expression to retrofit Get Rquest methods. but it can't be use default parameter. why? somebody has any solutions?

// WebServer.kt
interface WebServer{
    @GET("info/list/week")
    fun getWeekTrendingInfo(
        @Query("language") language: String = "en-US",
        @Header("authKey") authKey: String = ${BuildConfig.API_KEY}
    ): Call<InfoDTO>

    @GET("info/list/day")
    fun getDailyTrendingInfo(
        @Query("language") language: String = "en-US",
        @Header("authKey") authKey: String = ${BuildConfig.API_KEY}
    ): Call<InfoDTO>
}

// MainActivity.kt
override fun onCreate(savedInstanceState: Bundle?) {
    ...
    loadTrendingInfos(isWeek)
}

private fun loadTrendingInfos(isWeek: Boolean) {
    webService.run{
        val api = if (isWeek) this::getWeekTrendingInfo else this::getDailyTrendingInfo
        api().enqueue(InfoCallback { _, response -> // ERROR! IDE say No value passed for parameter
            adapter.submitList(response.body().infoList)
        })
    }
}

when i call api( ) in mainActivity's loadTrendingInfos function(not include param. cuz i want use default params), IDE say to me
No value passed for parameter 'p1', No value passed for parameter 'p2'

and val api's type is val api: KFunction2<String, String, Call<InfoDTO>>

so i try call api( ) like this (include param. not use default param)

api("en-US", "${BuildConfig.API_KEY}").enqueue(InfoCallback  { _, response ->
    adapter.submitList(response.body()?.movieList)
})

it work!

but i want know why can't use default parameter? and how to use default parameter this one?