PythonでYoutube Liveのアーカイブからチャットを取得したい

前提・実現したいこと

PythonでYoutube Liveのアーカイブからチャットを取得したいです。
こちらの質問のソースコードを参照しています。
https://teratail.com/questions/276731

発生している問題

pyファイルをcmdから実行し、エラーメッセージが返ってきます。
作成されるJSONファイル(タイトル名.Json)を開いても中身が空っぽです。

エラーメッセージ

SyntaxError
invalid syntax (<unknown>, line 1)
Comment data saved to タイトル名.json

該当のソースコード

python
1#!/usr/bin/env python3
2from bs4 import BeautifulSoup
3import ast
4import requests
5import re
6import sys
7import requests
8import requests_html # <= 追加
9
10# Verify user supplied a YouTube URL.
11#if len(sys.argv) == 1:
12#   print("Please provide a YouTube URL (e.g. ./YoutubeChatReplayCrawler.py YOUTUBE_VIDEO_URL)")
13#   sys.exit(0)
14# Produce a valid filename (from Django text utils).
15def get_valid_filename(s):
16   s = str(s).strip().replace(' ', '_')
17   return re.sub(r'(?u)[^-\w.]', '', s)
18# Set up variables for requests.
19#target_url = sys.argv[1]
20target_url = "https://www.youtube.com/watch?dummyID" #←適当に選んだ動画のURL
21dict_str = ''
22next_url = ''
23comment_data = []
24# session = requests.Session() この行を↓に置き換え
25session = requests_html.HTMLSession()
26headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36'}
27# Get the video page.
28html = session.get(target_url)
29# soup = session.get(target_url) この行を↓に置き換え
30resp = session.get(target_url)
31resp.html.render(sleep=3)  # <= 追加。レンダリングを完了させるため3秒待ちます。
32# soup = BeautifulSoup(html.text, 'html.parser')　　<=　ここは不要なのでコメントアウトする。
33# Retrieve the title and sanitize so it is a valid filename.
34# title = soup.find_all('title') この行を↓に置き換え
35title = resp.html.find('title')
36title = title[0].text.replace(' - YouTube', '')
37title = get_valid_filename(title)
38# Regex match for emoji.
39RE_EMOJI = re.compile('[\U00010000-\U0010ffff]', flags=re.UNICODE)
40# Find any live_chat_replay elements, get URL for next live chat message.
41# for iframe in soup.find_all("iframe"):
42#     if("live_chat_replay" in iframe["src"]):
43#         next_url = iframe["src"]
44# この3行を↓に置き換え
45for iframe in resp.html.find("iframe"):
46    if "live_chat_replay" in iframe.attrs["src"]:
47        next_url = "".join(["https://www.youtube.com", iframe.attrs["src"]])
48if not next_url:
49   print("Couldn't find live_chat_replay iframe. Maybe try running again?")
50   sys.exit(0)
51# TODO - We should fail fast if next_url is empty, otherwise you get error:
52# Invalid URL '': No schema supplied. Perhaps you meant http://?
53# TODO - This loop is fragile. It loops endlessly when some exceptions are hit.
54while(1):
55   try:
56       html = session.get(next_url, headers=headers)
57       soup = BeautifulSoup(html.text, 'lxml')
58       # Loop through all script tags.
59       for script in soup.find_all('script'):
60           script_text = str(script)
61           if 'ytInitialData' in script_text:
62               dict_str = ''.join(script_text.split(" = ")[1:])
63       # Capitalize booleans so JSON is valid Python dict.
64       dict_str = dict_str.replace("false", "False")
65       dict_str = dict_str.replace("true", "True")
66       # Strip extra HTML from JSON.
67       dict_str = re.sub(r'};.*\n.+</script>', '}', dict_str)
68       # Correct some characters.
69       dict_str = dict_str.rstrip(" \n;")
70       # TODO: I don't seem to have any issues with emoji in the messages.
71       # dict_str = RE_EMOJI.sub(r'', dict_str)
72       # Evaluate the cleaned up JSON into a python dict.
73       dics = ast.literal_eval(dict_str)
74       # TODO: On the last pass this returns KeyError since there are no more
75       # continuations or actions. Should probably just break in that case.
76       continue_url = dics["continuationContents"]["liveChatContinuation"]["continuations"][0]["liveChatReplayContinuationData"]["continuation"]
77       print('Found another live chat continuation:')
78       print(continue_url)
79       next_url = "https://www.youtube.com/live_chat_replay?continuation=" + continue_url
80       # Extract the data for each live chat comment.
81#         for samp in dics["continuationContents"]["liveChatContinuation"]["actions"][1:]:
82# これだと、チャットデータのブロックごとに最初の行が欠落するため、下記のようにする。
83       for samp in dics["continuationContents"]["liveChatContinuation"]["actions"]:
84           comment_data.append(str(samp) + "\n")
85   # next_urlが入手できなくなったら終わり
86   except requests.ConnectionError:
87       print("Connection Error")
88       continue
89   except requests.HTTPError:
90       print("HTTPError")
91       break
92   except requests.Timeout:
93       print("Timeout")
94       continue
95   except requests.exceptions.RequestException as e:
96       print(e)
97       break
98   except KeyError as e:
99       error = str(e)
100       if 'liveChatReplayContinuationData' in error:
101           print('Hit last live chat segment, finishing job.')
102       else:
103           print("KeyError")
104           print(e)
105       break
106   except SyntaxError as e:
107       print("SyntaxError")
108       print(e)
109       break
110       # continue #TODO
111   except KeyboardInterrupt:
112       break
113   except Exception:
114       print("Unexpected error:" + str(sys.exc_info()[0]))
115# Write the comment data to a file named after the title of the video.
116with open(title + ".json", mode='w', encoding="utf-8") as f:
117   f.writelines(comment_data)
118print('Comment data saved to ' + title + '.json')
119

試したこと

関連した質問から実施項目を検討しました。

https://teratail.com/questions/263421?link=qa_related_pc
https://teratail.com/questions/278254?link=qa_related_pc
https://teratail.com/questions/297389?link=qa_related_pc
https://teratail.com/questions/275236?link=qa_related_pc
0. bs4(BeautifulSoup)に不具合があると考え、バージョンを確認し再インストールを実施しました。
pip list
Package Version

appdirs 1.4.4
beautifulsoup4 4.9.3
bs4 0.0.1
cachetools 4.1.1
certifi 2020.6.20
chardet 4.0.0
cssselect 1.1.0
decorator 4.4.2
fake-useragent 0.1.11
ffmpeg 1.4
ffmpeg-python 0.2.0
future 0.18.2
google-api-core 1.22.1
google-api-python-client 1.10.0
google-auth 1.20.1
google-auth-httplib2 0.0.4
googleapis-common-protos 1.52.0
httplib2 0.18.1
idna 2.10
lxml 4.6.2
parse 1.16.0
pip 21.0
protobuf 3.13.0
py 1.9.0
pyasn1 0.4.8
pyasn1-modules 0.2.8
pyee 7.0.2
pyppeteer 0.2.2
pyquery 1.4.1
pytz 2020.1
requests 2.25.1
requests-html 0.10.0
retry 0.9.2
rsa 4.6
selenium 3.141.0
setuptools 41.2.0
six 1.15.0
soupsieve 2.0.1
tqdm 4.48.2
uritemplate 3.0.1
urllib3 1.26.3
w3lib 1.22.0
websockets 8.1
youtube-dl 2021.1.24.1
0. リファレンスの確認
http://kondou.com/BS4/
https://www.crummy.com/software/BeautifulSoup/