random_youtube.py

import random
import requests
from time import sleep

while True:
    random_id = ''.join(random.choices('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_', k=11))
    url = 'https://www.youtube.com/watch?v=' + random_id
    r = requests.get(url)
    if r.text.find('This video is unavailable') == -1:
        print(url)
        break
    sleep(2)