xlwt包已经下载并安装，可是无法创建？？？不知为何？

heroking146

import xlwt


workbook = xlwt.Workbook(encoding = 'utf-8')  # 创建workbook 对象
worksheet = workbook.add_sheet('sheet1')    # 创建工作表
worksheet.write(0,0,'hello')            # 写入数据，第一行参数行，第二行为列，第三个为内容。
workbook.save('student.xls')

显示如下错误：
workbook = xlwt.Workbook(encoding = 'utf-8')  # 创建workbook 对象
AttributeError: partially initialized module 'xlwt' has no attribute 'Workbook' (most likely due to a circular import)

heroking146

most likely due to a circular import？？？？？