kotlin fun ExistingClass.newFunctionName() { } kotlin package com.example.myapplication import androidx.fragment.app.Fragment import android.widget.Toast fun Fragment.showToast(message: String) { Toast.makeText(context, message, Toast.LENGTH_SHORT).show() } kotlin val fragment = NavigationFragment() fragment.showToast("Hello, World!") FragmentKt.showToast(fragment, "Hello, World!")