How to use the pytube.YouTube function in pytube

def validate_dataset(yt_uri, matching, in_stage, out_stage):
	# Use vid as the diretory name for download and processing
	vids = parse_qs(urlparse(yt_uri).query, keep_blank_values=True).get('v')
	vid = None if vids == None else vids[0]

	v_dir = os.path.join(data_path, vid)
	in_dir = os.path.join(v_dir, in_stage)
	out_dir = os.path.join(v_dir, out_stage)
	ext_dir = os.path.join(v_dir, out_stage + 'ext')

	# Get information on the YouTube content
	try:
		yt = YouTube(yt_uri)
	except:
		e = sys.exc_info()[0]
		print("Exception: {}".format(e))
		sys.exit(1)

	# Creating array of wav files
	files = []
	for file in os.listdir(in_dir):
		if file.endswith('.wav'):
			files.append(file)
	files.sort()

	os.makedirs(out_dir, exist_ok=True)
	os.makedirs(ext_dir, exist_ok=True)

	# Speech client

def getYoutubeUrl(input_url):
    if input_url[:32] == "https://www.youtube.com/watch?v=":
        yt = YouTube(input_url)  # additional sanitization needed
        uid = input_url[32:]
    elif input_url[:31] == "http://www.youtube.com/watch?v=":
        yt = YouTube(input_url)  # additional sanitization needed
        uid = input_url[31:]
    else:
        try:
            yt = YouTube("https://www.youtube.com/watch?v=%s" % input_url)
        except Exception as e:
            sys.exit("Error message: %s" % format(e))

    videos = yt.get_videos()
    for video in videos:
        print(video)
    yt.set_filename("intro-%s" % input_url)

    video = yt.get('mp4', '360p')

    return video.url

def retrieve_keyword_audio(vid, keyword):
    audio_index = 0
    v_url = URL_TEMPLATE.format(vid)
    youtube = YouTube(v_url)

    if int(youtube.length) > 2700:
        # only consider video < 45 mins
        return audio_index

    caption = youtube.captions.get_by_language_code('en')
    if caption:
        # retrieve audio from video
        youtube.streams.first().download(output_path=TEMP_DIR, filename=vid)

        temp_file_name = TEMP_DIR+vid
        if not os.path.isfile(temp_file_name + ".mp4"):
            return audio_index

        time.sleep(1) # need to wait before ffmpeg takes in as input file
        cmd = FFMPEG_TEMPLATE.format(temp_file_name).split()

cp.print_progress(i + 1, " / ", args.size, " - ", url)

        if url in url_set:
            cp.print_warning("video is already processed", url)
            continue

        url_set.add(url)

        if continuing:
            if url != args.continue_from:
                continue
            else:
                continuing = False

        try:
            video = PyTube(util.get_youtube_url(url))
        except Exception as exception:
            cp.print_error("failed to generate PyTube representation for video ", url)
            cp.print_error(exception)
            continue
        if int(video.length) > args.video_length:
            continue

        caption = video.captions.get_by_language_code('en')
        if not caption:
            cp.print_warning("no caption available for video - ", url)
            continue

        try:
            srt_captions = caption.generate_srt_captions().split('\n\n')
        except Exception as exception:
            cp.print_error("failed to retrieve srt for video - ", url)

def get_yt(link):
    try:
        # object creation using YouTube which was imported in the beginning
        yt = YouTube(link, )
    except:
        print("YT Error")
        return None

    return yt

def downloadYtMp4(yURL, dlDir=os.getcwd()):
    #find youtube video
    yt = YouTube(yURL)
    #filter to only mp4 files and take last in list (sorted lowest to highest quality)
    hqMp4 = yt.filter('mp4')[-1]
    #strip quality from video info.. example video info:
    m = re.search("- (\d\d\dp) -", str(hqMp4))
    #save quality capturing group
    quality = m.group(1)
    #get mp4 video with highest quality found
    video = yt.get('mp4', quality)
    #download and save video to specified dir
    video.download(dlDir)

try:
                os.mkdir(parent_full_path)
            except OSError:
                pass

        category_full_path = parent_full_path + "/" + video_list[ii]['category']

        if not os.path.exists(category_full_path):
            try:
                os.mkdir(category_full_path)
            except OSError:
                pass

        video_url = video_list[ii]['url']
        try:
            youtube = YouTube(video_url)
        except:
            error_list.append(video_list[ii])
            error_list_indices.append(ii)
            print "ActivityNet V{0}: {1:.2f}% File ".format(version, float(ii) / float(
                len(video_list)) * 100) + category_full_path + ' !! YOUTUBE ERROR !!'
            continue

        filename = youtube.filename
        filename = re.sub('[^a-zA-Z0-9]','', filename)

        youtube.set_filename(filename)

        temp_path = "/home/damien/temp/"
        video = youtube.videos[-2]
        video_full_path = temp_path + filename + '.' + video.extension
        outvideo_path = os.path.join(category_full_path, filename + ".avi")

def initialYouWork(self,url):
        video_list = pytube.YouTube(url)
        #로딩바 계산
        video_list.register_on_progress_callback(self.showProgressDownLoading)
        self.youtb = video_list.streams.all()
        self.streamCombobox.clear()
        for q in self.youtb:
            #print('step1',q.itag,q.mime_type,q.abr)
            tmp_list, str_list = [], []
            tmp_list.append(str(q.mime_type or ''))
            tmp_list.append(str(q.res or ''))
            tmp_list.append(str(q.fps or ''))
            tmp_list.append(str(q.abr or ''))

            #print('step_2',tmp_list)
            str_list = [x for x in tmp_list if x != '']
            #print('step3',str_list)
            print('join',','.join(str_list))

def handle_answer(self, message_entity=None):
        message = helper.clean_message(message_entity)
        if is_youtube_url(message):
            yt = YouTube(message)
            video = get_default_video(yt)

            path = "app/assets/videos/" + yt.filename + ".mp4"
            if os.path.exists(path):
                os.remove(path)

            video.download('app/assets/videos')
            mac.send_video(self.instance, self.conversation, path, caption="video")