protected function calculate_totals() {
		$this->set_total( 'total', round( $this->get_total( 'items_total', true ) + $this->get_total( 'fees_total', true ) + $this->get_total( 'shipping_total', true ) + wc_round_tax_total( array_sum( $this->get_merged_taxes( true ) ), 0 ), 0 ) );
		$this->cart->set_total_tax( array_sum( $this->get_merged_taxes( false ) ) );

		// Allow plugins to hook and alter totals before final total is calculated.
		if ( has_action( 'woocommerce_calculate_totals' ) ) {
			do_action( 'woocommerce_calculate_totals', $this->cart );
		}

		// Allow plugins to filter the grand total, and sum the cart totals in case of modifications.
		$this->cart->set_total( max( 0, apply_filters( 'woocommerce_calculated_total', $this->get_total( 'total' ), $this->cart ) ) );
	}