def add_columns(workbook, worksheet, columns):
    """
    Add columns to a worksheet
    """
    bold = workbook.add_format({'bold': True})
    col = 0
    col_widths = []
    for item in columns:
        worksheet.write(0, col, item, bold)
        col_widths.append(len(str(item)))
        col += 1
    return col_widths