PythonでGoogle Drive APIを使ってファイルの変更履歴にアクセスできない

前提・実現したいこと

Google Drive API v3を使ってPythonプログラムからGoogle Drive上のファイルの変更履歴を取得したいです。
変更履歴取得のところでエラーがでて、ログインが必要なようですが方法が分かりません。

発生している問題・エラーメッセージ

下に示すコードのservice.changes().list(pageToken=page_token, spaces='drive').execute()部分で以下のエラーが出ました。

File "/Users/***/.pyenv/versions/3.8.2/lib/python3.8/site-packages/googleapiclient/http.py", line 907, in execute
    raise HttpError(resp, content, uri=self.uri)
googleapiclient.errors.HttpError: <HttpError 400 when requesting https://www.googleapis.com/drive/v3/changes?pageToken=XXXXXX&spaces=drive&alt=json returned "Invalid Value">

エラー文中のhttps://www.googleapis.com/drive/v3/changes?pageToken=...を開くと、

{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "required",
    "message": "Login Required",
    "locationType": "header",
    "location": "Authorization"
   }
  ],
  "code": 401,
  "message": "Login Required"
 }
}

が表示されました。

該当のソースコード

Python
1import pickle, os.path
2
3from googleapiclient.discovery import build
4from google_auth_oauthlib.flow import InstalledAppFlow
5from google.auth.transport.requests import Request
6from google.oauth2 import service_account
7
8
9# ========================== Constants ==========================
10SCOPES = [
11	'https://www.googleapis.com/auth/drive',
12	'https://www.googleapis.com/auth/documents'
13]
14# ===============================================================
15
16
17def _get_credidential_oauth():
18	"""
19	Return type: <class \'google.oauth2.credentials.Credentials\'>
20
21	The file token.pickle stores the user's access and refresh tokens, and is
22	created automatically when the authorization flow completes for the first
23	time.
24	"""
25
26	creds = None
27
28	if os.path.exists('token.pickle'):
29		with open('token.pickle', 'rb') as token:
30			creds = pickle.load(token)
31	# If there are no (valid) credentials available, let the user log in.
32	if not creds or not creds.valid:
33		if creds and creds.expired and creds.refresh_token:
34			creds.refresh(Request())
35		else:
36			flow = InstalledAppFlow.from_client_secrets_file(
37				'credentials.json', SCOPES)
38			creds = flow.run_local_server(port=0)
39		# Save the credentials for the next run
40		with open('token.pickle', 'wb') as token:
41			pickle.dump(creds, token)
42
43	return creds
44
45
46def main():
47	creds = _get_credidential_oauth()
48	service = build('drive', 'v3', credentials=creds)
49	service_doc = build('docs', 'v1', credentials=creds)  # 使ってないです
50
51	edit_hists = []
52	page_token = service.changes().getStartPageToken().execute()
53	while page_token is not None:
54		response = service.changes().list(pageToken=page_token, spaces='drive').execute()  # エラー箇所
55		for change in response.get('changes'):
56			edit_hists.append(change)
57
58		if 'newStartPageToken' in response:
59			# Last page, save this token for the next polling interval
60			saved_start_page_token = response.get('newStartPageToken')
61		page_token = response.get('nextPageToken')
62
63	page_token = response.get('nextPageToken')
64
65
66if __name__ == '__main__':
67	main()
68