private function retrieveUsedModifiers($data)
    {
        $usedTypes = array_merge(
                $this->retrieveUsedFiltersType($data[ExportType::FILTER_KEY]),
                $this->retrieveUsedAggregatorsType($data[ExportType::AGGREGATOR_KEY])
                );
        
        $this->logger->debug('Required types are '.implode(', ', $usedTypes), 
                array('class' => self::class, 'function' => __FUNCTION__));
        
        return array_unique($usedTypes);
    }