python中使用xlsxwriter模块将程序生成的数据导入excel表格会覆盖问题怎么解决？

Question

如：程序1：
import xlsxwriter
workbook = xlsxwriter.Workbook('Demo1.xlsx')
worksheet = workbook.add_worksheet()
worksheet.write('A1', 'Hello World！')
workbook.close()
程序2：
import xlsxwriter
workbook = xlsxwriter.Workbook('Demo1.xlsx')
worksheet = workbook.add_worksheet()
worksheet.write('A2', '你好，世界！')
workbook.close()
excel中只有A2部分的