Limit Cart Weight

<?php
/*
Plugin Name: Limit Cart Weight
Plugin URI: https://www.damiencarbery.com/
Description: Prevent checkout when cart is above a certain weight.
Author: Damien Carbery
Author URI: https://www.damiencarbery.com
Version: 0.1
*/

// Based on: https://www.cloudways.com/blog/set-purchase-limits-on-woocommerce/
add_action( 'woocommerce_check_cart_items', 'cldws_set_weight_requirements' );
function cldws_set_weight_requirements() {
    // Only run in the Cart or Checkout pages
    if( is_cart() || is_checkout() ) {
        // Set the maximum weight before checking out
        $maximum_weight = 70;
        // Get the Cart's content total weight
        $cart_contents_weight = WC()->cart->get_cart_contents_weight();
        // Compare values and add an error is Cart's total weight
        if( $cart_contents_weight > $maximum_weight  ) {
            // Display our error message
            wc_add_notice( sprintf('<strong>Your order must be less than %s%s before checking out.</strong>'
                . '<br />Current cart weight: %s%s',
                $maximum_weight,
                get_option( 'woocommerce_weight_unit' ),
                $cart_contents_weight,
                get_option( 'woocommerce_weight_unit' ),
                get_permalink( wc_get_page_id( 'shop' ) )
                ),
                'error' );
        }
    }
}