protected function createXlRelsFolder()
    {
        $this->xlRelsFolder = $this->createFolder($this->xlFolder, self::RELS_FOLDER_NAME);
        return $this;
    }
protected function createXlRelsFolder()
    {
        $this->xlRelsFolder = $this->createFolder($this->xlFolder, self::RELS_FOLDER_NAME);
        return $this;
    }
protected function createXlRelsFolder ( ) { $ this -> xlRelsFolder = $ this -> createFolder ( $ this -> xlFolder , self :: RELS_FOLDER_NAME ) ; return $ this ; }
Creates the "_rels" folder under the "xl" folder

@return FileSystemHelper
@throws \Box\Spout\Common\Exception\IOException If unable to create the folder
Creates the _rels folder under the xl folder