public function getReportMetadata(
        array $idSites,
        $hideMetricsDoc = '',
        $showSubtableReports = '',
        array $optional = []
    )
    {
        return $this->_request('API.getReportMetadata', [
            'idSites' => $idSites,
            'hideMetricsDoc' => $hideMetricsDoc,
            'showSubtableReports' => $showSubtableReports,
        ], $optional);
    }