如何将文件合并为一个带断线的文件？

def merge_files(file_list, output_file):
    with open(output_file, 'wb') as output:
        for file_name in file_list:
            with open(file_name, 'rb') as file:
                output.write(file.read())

def merge_files_with_resume(file_list, output_file, resume_file):
    merged_size = 0
    if os.path.exists(resume_file):
        with open(resume_file, 'r') as resume:
            merged_size = int(resume.read())

    with open(output_file, 'ab') as output:
        for file_name in file_list:
            file_size = os.path.getsize(file_name)
            if merged_size >= file_size:
                merged_size -= file_size
                continue

            with open(file_name, 'rb') as file:
                file.seek(merged_size)
                output.write(file.read())

            merged_size = 0

    if os.path.exists(resume_file):
        os.remove(resume_file)