问通过YouTube数据API下载非拥有视频的封闭字幕[Python]

EN

videoID = getVideo(videoURL)
request = youtube.videos().list(
    part="snippet,contentDetails,statistics",
    id=videoID
)
response = request.execute()
items = response.get("items")[0]
contentDetails = items["contentDetails"]
caption = contentDetails["caption"]

if(caption):
    print("Video contains closed captions!")
else:
    print("Video does not contain closed captions.")

#get caption info
if(caption):
    caption_info = youtube.captions().list(part='id', videoId=videoID).execute().get('items', [])
    caption_str = youtube.captions().download(id=caption_info[0]['id'], tfmt='srt').execute()

SCOPES = ["https://www.googleapis.com/auth/youtube.force-ssl"]

def youtube_authenticate():
    os.environ["OAUTHLIB_INSECURE_TRANSPORT"] = "1"
    api_service_name = "youtube"
    api_version = "v3"
    client_secrets_file = "credentials.json"
    creds = None
    
    #check if authentication has already been completed
    if os.path.exists("token.pickle"):
        with open("token.pickle", "rb") as token:
            creds = pickle.load(token)
    #perform the authentication (1 time only)
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(client_secrets_file, SCOPES)
            creds = flow.run_local_server(port=0)
        # save the authenticated credentials
        with open("token.pickle", "wb") as token:
            pickle.dump(creds, token)

    return build(api_service_name, api_version, credentials=creds)