Validate SSL certificates with Python 3

# -*- encoding: utf-8 -*-
# pip install pyopenssl, idna

from OpenSSL import SSL
from cryptography import x509
from cryptography.x509.oid import NameOID
import idna

from socket import socket
from collections import namedtuple

HostInfo = namedtuple(field_names='cert hostname peername', typename='HostInfo')

HOSTS = [
    ('facebook.com', 443),
    ('google.com', 443),
]

def verify_cert(cert, hostname):