public function get($idOrKey, array $fields = null)
    {
        $parameters = $fields ?
            sprintf(
                '?%s',
                $this->createUriParameters(
                    ['fields' => implode(',', $fields)]
                )
            )
            : ''
        ;

        return $this->getRequest(sprintf('issue/%s%s', $idOrKey, $parameters));
    }