protected function validateIdentity(SaleInterface $sale, Constraint $constraint)
    {
        /** @var Sale $constraint */
        if (null === $sale->getCustomer()) {
            if (null === $sale->getCustomerGroup()) {
                $this->context
                    ->buildViolation($constraint->customer_group_is_required_if_no_customer)
                    ->atPath('customerGroup')
                    ->addViolation();
            }
            if (0 == strlen($sale->getEmail())) {
                $this->context
                    ->buildViolation($constraint->email_is_required_if_no_customer)
                    ->atPath('email')
                    ->addViolation();
            }

            IdentityValidator::validateIdentity($this->context, $sale);
        }
    }