public function add_shipping( $shipping_rate ) {
		wc_deprecated_function( 'WC_Order::add_shipping', '3.0', 'a new WC_Order_Item_Shipping object and add to order with WC_Order::add_item()' );

		$item = new WC_Order_Item_Shipping();
		$item->set_props( array(
			'method_title' => $shipping_rate->label,
			'method_id'    => $shipping_rate->id,
			'total'        => wc_format_decimal( $shipping_rate->cost ),
			'taxes'        => $shipping_rate->taxes,
			'order_id'     => $this->get_id(),
		) );
		foreach ( $shipping_rate->get_meta_data() as $key => $value ) {
			$item->add_meta_data( $key, $value, true );
		}
		$item->save();
		$this->add_item( $item );
		wc_do_deprecated_action( 'woocommerce_order_add_shipping', array( $this->get_id(), $item->get_id(), $shipping_rate ), '3.0', 'woocommerce_new_order_item action instead.' );
		return $item->get_id();
	}