WooCommerce: Change Select Options Button Text for variable products (ok)

add_filter( 'woocommerce_dropdown_variation_attribute_options_args', 'dropdown_variation_attribute_options', 10, 1 );
  function dropdown_variation_attribute_options( $args ){
    if( 'pa_size' == $args['attribute'] ) $args['show_option_none'] = __( 'Kích thước', 'woocommerce' );
    return $args;
  }