private function getDefaultHttpClientOptions(array $options = []): array
    {
        $headers = [];

        if ($this->token !== null) {
            $headers['Authorization'] = 'Bearer '.$this->token;
        }

        $languagesInOptions = (array_key_exists('headers', $options) &&
            array_key_exists('Accept-Language', $options['headers']));
        if ($this->languages !== null && $languagesInOptions === false) {
            $headers['Accept-Language'] = join(', ', $this->languages);
        }

        if ($this->version !== null) {
            $headers['Accept'] = 'application/vnd.thetvdb.v'.$this->version;
        }

        $options['http_errors'] = false;

        return array_merge_recursive(['headers' => $headers], $options);
    }