如何在python中写入文本文件的顶行

with open('file.txt', 'r+') as file:
    content = file.read()
    file.seek(0, 0)
    file.write('Top line\n' + content)

import shutil

with open('file.txt', 'r') as file:
    with open('temp.txt', 'w') as temp:
        temp.write('Top line\n')
        shutil.copyfileobj(file, temp)

shutil.move('temp.txt', 'file.txt')

import fileinput

with fileinput.FileInput('file.txt', inplace=True) as file:
    for line in file:
        if file.isfirstline():
            print('Top line')
        print(line, end='')