protected function renderColumn($column, $index)
    {
        if (is_string($this->template)) {
            return strtr($this->template, [
                '{label}' => $column->renderHeaderCell(),
                '{value}' => $column->renderDataCell($this->model, $this->model->getPrimaryKey(), 0),
            ]);
        }

        return call_user_func($this->template, $column, $index, $this);
    }