public function getLeadsByFilterType($filterType, $filterValues, $fields = array(), $nextPageToken = null, $returnRaw = false)
    {
        $args['filterType'] = $filterType;
        $args['filterValues'] = $filterValues;

        if ($nextPageToken) {
            $args['nextPageToken'] = $nextPageToken;
        }

        if (count($fields)) {
            $args['fields'] = implode(',', $fields);
        }

        return $this->getResult('getLeadsByFilterType', $args, false, $returnRaw);
    }