public function deleteFailedLoginAttempts($maxAge = null)
    {
        $sql = 'DELETE FROM FailedLoginAttempts';
        if ($maxAge) {
            $platform = $this->connection->getDatabasePlatform();
            $sql .= ' WHERE flaTimestamp <= ' . $platform->getDateSubSecondsExpression($platform->getNowExpression(), (int) $maxAge);
        }

        return (int) $this->connection->executeQuery($sql)->rowCount();
    }