Piwik\Plugins\Referrers\API::getNumberOfDistinctSearchEngines PHP Method

    public function getNumberOfDistinctSearchEngines($idSite, $period, $date, $segment = false)
    {
        return $this->getNumeric(Archiver::METRIC_DISTINCT_SEARCH_ENGINE_RECORD_NAME, $idSite, $period, $date, $segment);
    }