diy.py

with open(r"c:\Users\admin\Documents\lesson13-1\sales_list.txt","r",encoding="utf-8")as file1:
    a=file1.readlines() 
final_sum=[]
for i in a:
    data=i.split()
    sum=0
    for sales in data[1:]:
        sum+=int(sales)
    result=data[0]+str(sum)+"/n"
    final_sum.append(result)
with open(r"c:\Users\admin\Documents\lesson13-5\new_sales_list.txt","w",encoding="utf-8")as file2:
    file2.writelines(final_sum)