protected function getProductIds( array $productItems )
	{
		$prodIds = [];

		foreach( $productItems as $product )
		{
			if( $product->getType() === 'select' ) {
				$prodIds = array_merge( $prodIds, array_keys( $product->getRefItems( 'product', 'default', 'default' ) ) );
			}
		}

		return $prodIds;
	}