public function getSingleScalarResult()
    {
        if (count($this->operation->getAttributes()) !== 1 || $this->isWildCardSelection()) {
            $selected = $this->isWildCardSelection() ? 'All' : count($this->operation->getAttributes());
            throw new LdapQueryException(sprintf(
                'When retrieving a single value you should only select a single attribute. %s are selected.',
                $selected
            ));
        }
        $attribute = $this->operation->getAttributes();
        $attribute = reset($attribute);
        $result = $this->getSingleResult();

        if (!$result->has($attribute)) {
            throw new AttributeNotFoundException(sprintf('Attribute "%s" not found for this LDAP object.', $attribute));
        }

        return $result->get($attribute);
    }