private function renderRow(array $row)
    {
        $output = [];
        $output[] = $this->charVertical;
        $columnNumber = 0;
        foreach ($row as $column => $value) {
            $output[] = $this->renderCell($columnNumber, $value, ' ');
            $output[] = $this->charVertical;
            $columnNumber++;
        }
        return implode('', $output);
    }