如何在不删除/替换原始文件中的任何单词的情况下将字符串写入文本文件？

def insert_string_to_file(file_path, insert_string, position):
    with open(file_path, 'r') as file:
        file_content = file.read()

    new_content = file_content[:position] + insert_string + file_content[position:]

    with open(file_path, 'w') as file:
        file.write(new_content)

file_path = 'example.txt'
insert_string = '这是要插入的字符串'
position = 5  # 插入位置，从0开始计数

insert_string_to_file(file_path, insert_string, position)