Custom field - Prodcut sub title

//Display the custom field on SINGLE product page below the title in ASTRA

add_action( 'astra_woo_single_title_after', 'subheading_display_below_title', 2 );
function subheading_display_below_title(){
    global $product;

    // Get the custom field value
    $subheading = get_post_meta( $product->get_id(), 'product_subheading', true );

    // Display
    if( ! empty($subheading) ){
        echo '<p class="subheading">'.$subheading.'</p>';
    }
}