(SEO) WooCommerce "No Index, No Follow" on cart, order, checkout- pages then using YOAST!

wc-noindex-nofollow.php

function woo_seo_noindex_special_pages () {
    global $post;

    $woocommerce_pages = array('cart', 'checkout', 'order-received', 'order-tracking',
                               'my-account', 'logout', 'lost-password', 'mijireh-secure-checkout');
    $slug = get_post($post)->post_name;

    if (in_array($slug, $woocommerce_pages)) {
       echo '<meta name="robots" content="noindex,follow"/>' . "\n";
    }
}
add_action('wpseo_head', 'woo_seo_noindex_special_pages');