Muncul Tulisan ---> fatal error: Uncaught ArgumentCountError: Too few arguments to function.....

Halo kawan2 semua, saya mengikuti tutorial membuat sistem login. namun ketika saya sudah memasukkan semua kode yang ada di video tersebut muncul pesan error seperti ini :

 Fatal error: Uncaught ArgumentCountError: Too few arguments to function cek_data(), 0 passed in D:\xampp\htdocs\sekolah-koding\belajar-php\loginregister\login.php on line 10 and exactly 2 expected in D:\xampp\htdocs\sekolah-koding\belajar-php\loginregister\functions\user.php:32 Stack trace: #0 D:\xampp\htdocs\sekolah-koding\belajar-php\loginregister\login.php(10): cek_data() #1 {main} thrown in D:\xampp\htdocs\sekolah-koding\belajar-php\loginregister\functions\user.php on line 32

kode di halaman login.php saya :

 <?php

require_once "core/init.php";

if(isset ($_POST['submit'])){
	$nama = $_POST['username'];
	$pass = $_POST['password'];

	if(!empty(trim($nama))&& !empty(trim($pass)) ){
		cek_data($nama, $pass);
	}else{
		echo 'tidak boleh kosong';
	}
}

require_once "view/header.php";

?>

<form action="login.php" method="post">
<label for="">Nama</label><br>
<input type="text" name="username"><br><br>

<label for="">Password</label><br>
<input type="password" name="password"><br><br>

<input type="submit" name="submit" value="daftar">
</form>

<?php

require_once "view/footer.php";

?>

kode di halaman user.php saya :

 <?php

function register_user($nama, $pass){
	global $link;

	$nama = mysqli_real_escape_string($link, $nama);
	$pass = mysqli_real_escape_string($link, $pass);

	$pass = password_hash($pass, PASSWORD_DEFAULT);
	$query ="INSERT INTO users (username, password) VALUES ('$nama', '$pass')";

	if(mysqli_query($link, $query)){
		return true;
	}else{
		return false;
	}

}

function register_cek_nama($nama){
	global $link;
	$nama = mysqli_real_escape_string($link, $nama);

	$query = "SELECT * FROM users WHERE username = '$nama'";

	if($result = mysqli_query($link, $query)){
		if(mysqli_num_rows($result) == 0)return true;
		else return false;
	}
}

function cek_data(String $nama, String $pass){
	global $link;

	$nama = mysqli_real_escape_string($link, $nama);
	$pass = mysqli_real_escape_string($link, $pass);

	$query = "SELECT password FROM users WHERE username='$nama' ";
	$result = mysqli_query($link, $query);
	$hash = mysqli_fetch_assoc($result)['password'];


	if (password_verify($pass, $hash)){
		die ('berhasil');
	}else{
	die ('gagal');
	}
}

?>

Saya menggunakan Xampp dengan PHP versi 7.1.6.

untuk mengatasi masalah tersebut, apa yang harus saya lakukan? saya ucapkan terima kasih sebelumnya.......