有什么方法可以使用python以增量顺序在文件中添加数据吗

我试图使用python在文件“example.txt”中添加数据。每次运行“Test.py”文件时,我都希望以增量顺序在文件中添加数据。 下面是我试过的代码

i = 0
for i in reversed(range(0,20,1)):
    i = i+1
    value = ("hash%s"%i)

index = 0

with open("Test.txt", "r") as f:
   contents = f.readlines()

contents.insert(index, value)


with open("Test.txt", "w") as f:
   contents = "".join(contents)
   f.write(contents)

我的不满是:

hash1hash1hash1

预期产出:

On 1st run of code output should resemble: hash1
On 2nd run of code output should resemble: hash2
On 3rd run of code output should resemble: hash3