Show and Hide methods throw an Unresolved reference error with Kotlin

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
}
```

Start with the SlideUpBuilder construction and the button-click snippet, then reproduce Kotlin's Unresolved reference error for show() and hide(). Done means the supported way to invoke those methods compiles for this example; the issue names no files or tests.

Written by the indexing model from the issue text.