public static function add_order_tax() {
		check_ajax_referer( 'order-item', 'security' );

		if ( ! current_user_can( 'edit_shop_orders' ) ) {
			wp_die( -1 );
		}

		$response = array();

		try {
			$order_id = isset( $_POST['order_id'] ) ? absint( $_POST['order_id'] ) : 0;
			$order    = wc_get_order( $order_id );

			if ( ! $order ) {
				throw new Exception( __( 'Invalid order', 'woocommerce' ) );
			}

			$rate_id = isset( $_POST['rate_id'] ) ? absint( $_POST['rate_id'] ) : '';

			if ( ! $rate_id ) {
				throw new Exception( __( 'Invalid rate', 'woocommerce' ) );
			}

			$data = get_post_meta( $order_id );

			// Add new tax.
			$item = new WC_Order_Item_Tax();
			$item->set_rate( $rate_id );
			$item->set_order_id( $order_id );
			$item->save();

			ob_start();
			include 'admin/meta-boxes/views/html-order-items.php';
			$response['html'] = ob_get_clean();
		} catch ( Exception $e ) {
			wp_send_json_error( array( 'error' => $e->getMessage() ) );
		}

		// wp_send_json_success must be outside the try block not to break phpunit tests.
		wp_send_json_success( $response );
	}