auto save

diy.py

 # 写入同学们的捐赠明细：'小兰：12本'、'小丽：11本'、'李文：9本'、'张伟：16本'
-with open(r"D:\桌面\text.txt",'w',encoding='utf-8') as file:
+with open(r"D:\桌面\text.txt",'a'',encoding='utf-8') as file:
     file.write('小兰：12本\n')