Restrict any wp page or post for any role

cbx_restrict_content.php

<?php
/**
 * Plugin Name:   CBX Simple Restrict Content
 * Description:   Simple or hard coded wordpress content restrict for any role
 * Author:        Codeboxr
 * Version:       1.0.0
 * Licence:       MIT
 * Author URI:    https://codeboxr.com
 */
//if you want to use this code in theme ignore lines from 1-10 or use code from 11 to bottom of this page.
add_action( 'wp', 'cbx_restrict_content' );

function cbx_restrict_content($content){
	//write_log($content);

	$post_page_id = '4565'; //post or page id which you want to restrict
	$role_name = 'contributor'; //specific role name/slug

	if(is_singular()){
		$post_id = intval(get_the_ID());

		$user_roles = array();
		if( is_user_logged_in() ) {
			$user = wp_get_current_user();
			$user_roles = ( array ) $user->roles;
		}

		if($post_id == $post_page_id && !in_array($role_name, $user_roles)){
			add_filter('the_content', 'cbx_restrict_content_message');
		}
	}

	return $content;
}

function cbx_restrict_content_message(){
	return 'Sorry, you are not allowed to view the content of this article/page';
}