public function getBucketsFlat($page = null, $perPage = null, $data = [])
    {
        $aBuckets = $this->getBuckets($page, $perPage, $data);
        $aOut     = [];

        foreach ($aBuckets as $oBucket) {
            $aOut[$oBucket->id] = $oBucket->label;
        }

        return $aOut;
    }