python openpyxl工作表自动调整大小column_dimensions -失败

from openpyxl import Workbook
from openpyxl.utils import get_column_letter

# 创建一个新的工作簿
wb = Workbook()

# 选择活动工作表
ws = wb.active

# 设置一些示例数据
ws['A1'] = 'Hello'
ws['B1'] = 'World'
ws['C1'] = 'Openpyxl'

# 自动调整列的大小
for column in ws.columns:
    max_length = 0
    column_letter = get_column_letter(column[0].column)
    for cell in column:
        try:
            if len(str(cell.value)) > max_length:
                max_length = len(cell.value)
        except:
            pass
    adjusted_width = (max_length + 2)
    ws.column_dimensions[column_letter].width = adjusted_width

# 保存工作簿
wb.save('example.xlsx')