使用 wordlist_filename，根据讲义解密 input_file指令，并返回plaintext。请问怎么修改代码

from typing import TextIO # 具体注释

def decrypt(input_file: TextIO, wordlist_filename: str) -> str:
"""
使用 wordlist_filename，根据讲义解密 input_file
指令，并返回plaintext。
"""
len_msg = len(msg)

if name == "main":

# Sample input from the handout -- you can tweak this if you like
print(decrypt(open("book1.txt"), "wordlist.txt"))

wordlist.txt 内是从a-z的单词
讲义.txt 如下
VILLAGERS
Luke Sawczak
Dan Zingaro*
Freddie Prinze Jr.
Arnold Rosenbloom

SONGS
People, I've Been Sad
Call Me Maybe
What a Man Gotta Do
Delete Forever

PARTIES
Dan Zingaro,Freddie Prinze Jr.,Arnold Rosenbloom
Arnold Rosenbloom,Luke Sawczak,Freddie Prinze Jr.
Dan Zingaro,Luke Sawczak
Freddie Prinze Jr.,Luke Sawczak,Arnold Rosenbloom

你应该提供讲义中的解密方式才能写代码