Restrict specific posts/pages in your WordPress site for members of a level, redirect other visitors away

my_restricted_posts_require_membership_level.php

<?php // copy from below

/**
 * Restrict specific posts/pages in your WordPress site for members of a level
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
function my_restricted_posts_require_membership_level() {
	global $post;
	
	// bail if PMPro isn't active
	if ( ! function_exists( 'pmpro_hasMembershipLevel' ) ) {
		return;
	}
	
	// Allow members of specified level ID(s)
	if ( pmpro_hasMembershipLevel( 1 ) ) {
		return;
	}

	// The level specified above is required to access these posts
	$restricted_posts = array( 651, 652, 769 ); // post ids here
	
	if ( in_array( $post->ID, $restricted_posts ) ) {
		wp_redirect( home_url() ); // redirect to home
		exit;
	}

}
add_action( 'template_redirect', 'my_restricted_posts_require_membership_level' );