Kotlin – How to add OnPageChangeListener in ViewPager

I found it is quite simple, but it took my time as I am new in kotlin. I hope it will save others time one day.

viewPager?.addOnPageChangeListener(object : ViewPager.OnPageChangeListener {

            override fun onPageScrollStateChanged(state: Int) {
            }

            override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {

            }
            override fun onPageSelected(position: Int) {

            }

        })

or we can implement ViewPager.OnPageChangeListener in our Activity or Fragment then just use viewPager?.addOnPageChangeListener(this) but make sure to implement overrided methods.