protected function prepare_line_items( $order ) {
		$this->delete_line_items();

		// Products.
		foreach ( $order->get_items( array( 'line_item', 'fee' ) ) as $item ) {
			if ( 'fee' === $item['type'] ) {
				$item_line_total = $this->number_format( $item['line_total'], $order );
				$this->add_line_item( $item->get_name(), 1, $item_line_total );
			} else {
				$product         = $item->get_product();
				$sku             = $product ? $product->get_sku() : '';
				$item_line_total = $this->number_format( $order->get_item_subtotal( $item, false ), $order );
				$this->add_line_item( $this->get_order_item_name( $order, $item ), $item->get_quantity(), $item_line_total, $sku );
			}
		}
	}