Python - Error http en consola al ingresar el enlace del video que quiero descargar. No muestra miniatura

from importlib.util import find_spec as find_lib
from os.path import expandvars as os_vars
from urllib.request import urlopen
from PIL import Image, ImageTk
import tkinter.filedialog
import tkinter
import pafy
import pip
import io

ret_values = {};

def getThumbnailURL(url):

counter = 0;
pos = 0;

for char in url:
if char == '?':
counter = 1;
if char == 'v':
if counter == 1:
counter = 2;
break;
pos += 1;

video_id = url[pos + 2:];

return "https://img.youtube.com/vi/%s/0.jpg" % video_id;

def downloadVideo():

choice = DVVar.get();

if choice == '':
return;

counter = 0;
for i in ret_values['videostreams']:
if str(i.resolution) + ', ' + i.extension == choice:
break;
counter += 1;

if counter >= len(ret_values['videostreams']):
return;

ret_values['videostreams'][counter].download(quiet=True, filepath=video_dir.get());

def downloadAudio():

choice = DAVar.get();

if choice == '':
return;

counter = 0;
for i in ret_values['audiostreams']:
if str(i.bitrate) + ', ' + i.extension == choice:
break;
counter += 1;

if counter >= len(ret_values['audiostreams']):
return;

ret_values['audiostreams'][counter].download(quiet=True, filepath=audio_dir.get());


def getVideoDir():


options = {};
options['mustexist'] = False;
options['title'] = 'Download folder';


dir_path = tkinter.filedialog.askdirectory(**options);
video_dir.config(state='normal');
video_dir.delete(0,'end');
video_dir.insert(0,dir_path);
video_dir.config(state='disabled');


def getAudioDir():


options = {};

options['mustexist'] = False;
options['title'] = 'Download folder';


dir_path = tkinter.filedialog.askdirectory(**options);
audio_dir.config(state='normal');
audio_dir.delete(0,'end');
audio_dir.insert(0,dir_path);
audio_dir.config(state='disabled');


def get(a,b,c):
url = url_entry.get();

tnURL = getThumbnailURL(url);


image_bytes = urlopen(tnURL).read();
im = Image.open(io.BytesIO(image_bytes));
tk_image = ImageTk.PhotoImage(im.resize((140, 110), Image.ANTIALIAS));
ret_values['photoholder'].configure(image=tk_image, width="140", height="110");
ret_values['photoholder'].image = tk_image;

if url == '':
return

video = pafy.new(url);

attr = {};

attr['title'] = video.title;
attr['rating'] = video.rating;
attr['viewcount'] = video.viewcount;
attr['author'] = video.author;
attr['length'] = video.length;
attr['duration'] = video.duration;
attr['likes'] = video.likes;
attr['dislikes'] = video.dislikes;

titlelbl.config(text="Title: " + attr['title']);
authorlbl.config(text="Author: " + attr['author']);
durationlbl.config(text="Duration: " + attr['duration']);
viewcountlbl.config(text="Views: " + str(attr['viewcount']));
likeslbl.config(text="Likes: " + str(attr['likes']));
dislikeslbl.config(text="Dislikes: " + str(attr['dislikes']));


videoStreams = video.streams;
audioStreams = video.audiostreams;


DVList = [str(i.resolution) + ', ' + i.extension for i in videoStreams];
DAList = [str(i.bitrate) + ', ' + i.extension for i in audioStreams];

DVDrop['menu'].delete(0, 'end');
DVDrop['menu'].delete(0, 'end');

DVVar.set('');
DAVar.set('');

for i in DVList:
DVDrop['menu'].add_command(label=i, command=tkinter._setit(DVVar, i));

for i in DAList:
DADrop['menu'].add_command(label=i, command=tkinter._setit(DAVar, i));

DVVar.set(DVList[0]);
DAVar.set(DAList[0]);

ret_values['videostreams'] = videoStreams;
ret_values['audiostreams'] = audioStreams;
ret_values['video'] = video;


if __name__ == '__main__':
master = tkinter.Tk();
master.title("YouTube Downloader");
master.minsize(width="800", height="270");
master.resizable(width=False, height=False);
master.geometry('800x270');
master.geometry('800x270+0+0');

ret_values['master'] = master;

tkinter.Label(master, text="Url").place(x=20,y=20);

url_var = tkinter.StringVar();
url_var.trace('w', get);
url_entry = tkinter.Entry(master, textvariable=url_var, width=120);
url_entry.place(x=50,y=20);

titlelbl = tkinter.Label(master, text="Title: ");
titlelbl.place(x=180,y=58);

authorlbl = tkinter.Label(master, text="Author: ");
authorlbl.place(x=180,y=78);

durationlbl = tkinter.Label(master, text="Duration: ");
durationlbl.place(x=180,y=98);

viewcountlbl = tkinter.Label(master, text="Views: ");
viewcountlbl.place(x=180,y=118);

likeslbl = tkinter.Label(master, text="Likes: ");
likeslbl.place(x=180,y=138);

dislikeslbl = tkinter.Label(master, text="Dislikes: ");
dislikeslbl.place(x=180,y=158);

DVList = [''];
DAList = [''];

DVVar = tkinter.StringVar(master);
DVVar.set('Quality');
DAVar = tkinter.StringVar(master);
DAVar.set('Quality');

DVDrop = tkinter.OptionMenu(master, DVVar, *DVList);
DVDrop.configure(width="12");
DVDrop.place(x=135,y=192);

DADrop = tkinter.OptionMenu(master, DAVar, *DAList);
DADrop.configure(width="12");
DADrop.place(x=135,y=222);

tkinter.Button(master, text="Download Video", command=downloadVideo, width=15, height=1).place(x=20,y=195);
tkinter.Button(master, text="Download Audio", command=downloadAudio, width=15, height=1).place(x=20,y=225);

video_dir = tkinter.Entry(master, width=80);
video_dir.insert(0,os_vars("%userprofile%")+'\\Downloads\\');
video_dir.config(state='disabled');
video_dir.place(x=260,y=197);

audio_dir = tkinter.Entry(master, width=80);
audio_dir.insert(0,os_vars("%userprofile%")+'\\Downloads\\');
audio_dir.config(state='disabled');
audio_dir.place(x=260,y=227);

tkinter.Button(master, text="...", command=getVideoDir, width=4, height=1).place(x=755,y=195);
tkinter.Button(master, text="...", command=getAudioDir, width=4, height=1).place(x=755,y=225);

im = ImageTk.PhotoImage(Image.frombytes('L', (140, 110), str.encode( ''.join(['\x00' for i in range(140*110)]) )));
photoHolder = tkinter.Label(master, image=im, bg='white', width="140", height="110");
photoHolder.place(x=20, y=60);

ret_values['photoholder'] = photoHolder;

master.mainloop();