如何在一定天数后删除.txt文件的部分？

import os
import time

def delete_files(directory, days):
    current_time = time.time()
    time_threshold = days * 24 * 60 * 60  # 转换为秒

    for filename in os.listdir(directory):
        file_path = os.path.join(directory, filename)
        if filename.endswith(".txt") and os.path.isfile(file_path):
            file_creation_time = os.path.getctime(file_path)
            if (current_time - file_creation_time) > time_threshold:
                os.remove(file_path)
                print(f"Deleted file: {file_path}")

# 调用函数删除指定目录下在一定天数后创建的.txt文件
delete_files("/path/to/directory", 30)