Show and Hide methods throw an Unresolved reference error with Kotlin

[sutherland007]

I'm trying to use show() and hide() but not working they throw an Unresolved reference.
here is my code:

        val slideUp: SlideUpBuilder = SlideUpBuilder(PlayerView)
        slideUp.withStartState(SlideUp.State.SHOWED)
        slideUp.withStartGravity(Gravity.TOP)
        slideUp.withAutoSlideDuration(500)
        slideUp.build()

Here is my button click code example:

btn_ShowPlayer.setOnClickListener{
         slideUp.show() //both show() and hide() throw an Unresolved reference error
}

[sutherland007]

After doing some code corrections, the methods are finally working.
Sorry for the inconvenience.