Telegram VOIP calls. What libraries are needed?

Question

Python

#!/usr/bin/env python3
# Telegram VOIP calls from python example
# Author Gabriel Jacobo https://mdqinc.com

import logging
import argparse
import os
import json
import base64
from telegram.client import Telegram
from tgvoip import call


def setup_voip( data):
# state['config'] is passed as a string, convert to object
data['state']['config'] = json.loads(data['state']['config'])
# encryption key is base64 encoded
data['state']['encryption_key'] = base64.decodebytes(data['state']['encryption_key'].encode('utf-8'))
# peer_tag is base64 encoded
for conn in data['state']['connections']:
conn['peer_tag'] = base64.decodebytes(conn['peer_tag'].encode('utf-8'))
call(data)

def handler(msg):
#print ("UPDATE >>>", msg)
if msg['@type'] == 'updateCall':
data = msg['call']
if data['id'] == outgoing['id'] and data['state']['@type'] = = 'callStateReady':
setup_voip(data)


if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument('api_id', help='API id') # https://my.telegram.org/ apps
parser.add_argument('api_hash', help='API hash')
parser.add_argument('phone', help='Phone nr originating call')
parser.add_argument('user_id', help='User ID to call')
parser.add_argument('dbkey', help='Database encryption key')
args = parser.parse_args()

tg = Telegram(api_id=args.api_id,
api_hash=args.api_hash,
phone=args.phone,
td_verbosity=5,
files_directory = os.path.expanduser("~/.telegram/" + args.phone),
database_encryption_key=args.dbkey)
tg.login()

# if this is the first run, library needs to preload all chats
# otherwise the message will not sent
r = tg.get_chats()
r.wait()


r = tg.call_method('createCall', {'user_id': args.user_id, 'protocol': {'udp_p2p': True, 'udp_reflector': True, 'min_layer': 65, 'max_layer': 65} })
r.wait()
outgoing = r.update

tg.add_handler(handler)
tg.idle() # blocking waiting for CTRL+C

Calls serve as notifications.
Problem running code.