Include multiple download IDs in limit one per customer in EDD

functions.php

add_action( 'edd_before_purchase_form', 'sd_set_purchase_limit_error' );
function sd_set_purchase_limit_error(){
	$user_id 		= get_current_user_id(); // Get the current customer's ID
	$downloads 		= edd_get_users_purchased_products( $user_id ); // Get all of the products the customer has purchased in the past
	$can_checkout 		= true; // Allow checkout for now
	$download_ids		= array( 1,2,3 ); //Whatever the IDs are that you want to check for
	foreach ( $download_ids as $download_id ){
		$in_cart 		= edd_item_in_cart( $download_id ); // Check to see if our download is in the customer's cart. Change 57 to your download's ID.
 
		if ( $in_cart == true ){ // If the item isn't in the customer's cart we don't need to go any further.
			if ( ! empty( $downloads ) ){ // If the customer hasn't purchased anything before we don't need to go any further.
				foreach ( $downloads as $download ){ // Loop through each product the customer has purchased before.
					switch ( $download->ID ) {
						case '1':
						case '2':
						case '3': // If the customer has purchased the product(s) we want to limit one per customer set an error message.
							edd_set_error( 'already_purchased', apply_filters( 'edd_pc_error_message', __( 'You have already purchased the one-per-customer plugin. There is a limit of one per customer. You can log out and purchase with a different account, or remove it from your cart with the link above.' ) ) );
							break;
 
						default:
							edd_unset_error( 'already_purchased' );
							break;
					}
				}
 
				edd_print_errors(); // Display the errors on the checkout page.
			}
		}
	}
}