save project

diy.py

 with open(r"c:\Users\Administrator\Documents\lesson13-1\sales_list.txt",'r',encoding="utf-8") as gstu:
 with open(r"c:\Users\Administrator\Documents\lesson13-1\sales_list.txt",'r',encoding="utf-8") as gstu:
-    a=file.read()
+    a=gstu.read()
     print(type(a[3:5]))
     print(type(a[3:5]))
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