protected function loadCartFromSession()
    {
        $cartIdInSession = $this
            ->cartSessionManager
            ->get();

        if (!$cartIdInSession) {
            return null;
        }

        $cart = $this
            ->cartRepository
            ->findOneBy([
                'id' => $cartIdInSession,
                'ordered' => false,
            ]);

        return ($cart instanceof CartInterface)
            ? $cart
            : null;
    }