public function addEntry($dn, $data)
    {
        $data = $this->normalizeData($data);

        if (! (@ldap_add($this->connection, $dn, $data))) {
            $code = @ldap_errno($this->connection);
            throw new PersistenceException(
                sprintf(
                    'Could not add entry %s: Ldap Error Code=%s - %s',
                    $dn,
                    $code,
                    ldap_err2str($code)
                )
            );
        }
    }