A little problem with Bottom Nav

Hi. I try to create a bottom menu with fragment. But the code has some error. Im new in this word of programation.

If someone could guide me I would be grateful

package com.example.splashscreen

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.MenuItem
import androidx.fragment.app.Fragment

class Principal : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_principal)

    var InicioFragment = InicioFragment()
    var mercadoFragment = mercadoFragment()
    var noticiasFragment = noticiasFragment()
    var senalesFragment = senalesFragment()
    var tutorialesFragment = tutorialesFragment()

    **bottomNavigationView**.setOnNavigationItemSelectedListener {**it**: MenuItem
    when(**it**.itemId){
        R.id.nav_inicio -> {
            setcurrentFragment(InicioFragment)

        }

        R.id.nav_mercado -> {
            setcurrentFragment(mercadoFragment)

        }

        R.id.nav_noticias -> {
            setcurrentFragment(noticiasFragment)

        }

        R.id.nav_senales -> {
            setcurrentFragment(senalesFragment)

        }

        R.id.nav_tutoriales -> {
            setcurrentFragment(tutorialesFragment)

        }
        else -> false
    }       }

}

private fun setcurrentFragment(fragment: Fragment) {
    supportFragmentManager.beginTransaction().apply { this: FragmentTransaction
    replace(R.id.containerView, Fragment)
        commit()

    }
}

}

Thx so much.

missing → after MenuItem ??

setOnNavigationItemSelectedListener {it: MenuItem -> 
   when (...