auto save

diy.py

+file1= open(r'C:\book.txt','w',encoding='utf-8')
+file1.write('小强:10本\n')
+file1.write('李明:15本\n')
+file1.close()
+
+with open(r'C:\book.txt','w',encoding='utf-8') as file:
+    file1.write('小强:10本\n')
+    file1.write('李明:15本\n')