public function set_h_align($location) {
        switch ($location) {
            case 'left':
                $this->format['alignment']['horizontal'] = PHPExcel_Style_Alignment::HORIZONTAL_LEFT;
                break;
            case 'center':
            case 'centre':
                $this->format['alignment']['horizontal'] = PHPExcel_Style_Alignment::HORIZONTAL_CENTER;
                break;
            case 'right':
                $this->format['alignment']['horizontal'] = PHPExcel_Style_Alignment::HORIZONTAL_RIGHT;
                break;
            case 'justify':
                $this->format['alignment']['horizontal'] = PHPExcel_Style_Alignment::HORIZONTAL_JUSTIFY;
                break;
            default:
                $this->format['alignment']['horizontal'] = PHPExcel_Style_Alignment::HORIZONTAL_GENERAL;
        }
    }