Enumerate each table column.

def table_format(self, columns, content):
        """
        Enumerate each table column.
        """
        result = []
        textw = TextWidget()
        for row in content:
            i = 0
            result_row = []
            for cell in row:
                result_row.append(textw.render(cell, **columns[i]))
                i += 1
            result.append(result_row)
        return (columns, result)