very basic example of M in mvp

CalculatorMVP.kt

class Calculator {
  //obviously a bit silly for a calculator but you get the idea, just think of this as business logic/data/state management
 fun add(v1: Int, v2: Int) {
    return v1 + v2 
 }
}

//in this case going to make the presenter stateful, even though in a real apps you shouldn't
class SomePresenter(val calculator: Calculator) {
 
  var currentValue = 0
  
  fun add(value: Int) {
   val result = calculator.add(v1,v2) 
   currentValue = result
   view.displayResult(currentValue)
  }
  
  interface View {
    fun displayResult(result: Int)
  }
}