Use the flanker library to get all the bad email addresses included in the list supplied on stdin

get_bad_email_address.py

#!/usr/bin/env python

# pip install flanker dnsq
#
# requirements.txt:
#   attrs==19.3.0
#   cffi==1.13.2
#   chardet==3.0.4
#   cryptography==2.8
#   dnspython==1.16.0
#   dnsq==1.1.6
#   expiringdict==1.2.0
#   flanker==0.9.11
#   idna==2.8
#   pkg-resources==0.0.0
#   ply==3.11
#   pycparser==2.19
#   regex==2020.1.8
#   six==1.14.0
#   tld==0.11.9
#   typing==3.7.4.1
#   WebOb==1.8.6

from collections import defaultdict
import sys

import flanker.addresslib
from flanker.addresslib import address


flanker.addresslib.set_mx_cache(defaultdict(lambda: None))


if __name__ == '__main__':
    for email in sys.stdin:
        email = email.strip()
        if not email:
            continue
        if not address.validate_address(email):
            print(email)