public function add($geoRegion)
    {
        if (is_array($geoRegion)) {
            $this->collection[] = new GeoRegion($geoRegion);
        } elseif (is_object($geoRegion) && $geoRegion instanceof GeoRegion) {
            $this->collection[] = $geoRegion;
        }

        return $this;
    }